Terminal device, base station device, and communication method for setting TTI channel

ABSTRACT

[Object] To provide a terminal device capable of efficiently performing communication in a communication system in which a base station device and the terminal device communicate with each other. 
     [Solution] A terminal device that communicates with a base station device includes: a higher layer processing unit configured to set an STTI channel setting through signaling of a higher layer from the base station device; and a receiving unit configured to receive a first PDSCH in a case in which the STTI channel setting is not set and receive a second PDSCH in a case in which the STTI channel setting is set. The first PDCCH is mapped to one or more resource blocks, the second PDCCH is mapped to one or more sub resource blocks, and the second PDSCH is demodulated using a reference signal mapped to a symbol including the sub resource block or a resource element before the symbol.

TECHNICAL FIELD

The present disclosure relates to a terminal device, a base stationdevice, and a communication method.

BACKGROUND ART

Wireless access schemes and wireless networks of cellular mobilecommunication (hereinafter also referred to as LTE-Advanced (LTE-A),LTE-Advanced Pro (LTE-A Pro), or Evolved Universal Terrestrial RadioAccess (EUTRA)) are under review in 3rd Generation Partnership Project(3GPP). Further, in the following description, LTE includes LTE-A, LTE-APro, and EUTRA. In LTE, a base station device (base station) is alsoreferred to as an evolved Node B (eNodeB), and a terminal device (amobile station, a mobile station device, or a terminal) is also referredto as a user equipment (UE). LTE is a cellular communication system inwhich a plurality of areas covered by a base station device are arrangedin a cell form. A single base station device may manage a plurality ofcells.

LTE is compatible with frequency division duplex (FDD) and time divisionduplex (TDD). LTE employing the FDD scheme is also referred to as FD-LTEor LTE FDD. TDD is a technology which enables full duplex communicationto be performed in at least two frequency bands by performing frequencydivision multiplexing on an uplink signal and a downlink signal. LTEemploying the TDD scheme is also referred to as TD-LTE or LTE TDD. TDDis a technology that enables full duplex communication to be performedin a single frequency band by performing time division multiplexing onan uplink signal and a downlink signal. The details of FD-LTE and TD-LTEare disclosed in Non-Patent Literature 1.

The base station device maps a physical channel and a physical signal tophysical resources configured on the basis of a predefined frameconfiguration and transmits the physical channel and the physicalsignal. The terminal device receives the physical channel and thephysical signal transmitted from the base station device. In LTE, aplurality of frame configuration types are specified, and datatransmission is performed using physical resources of a frameconfiguration corresponding to each frame configuration type. Forexample, a frame configuration type 1 is applicable to FD-LTE, and aframe configuration type 2 is applicable to TD-LTE. The details of theframe structure are disclosed in Non-Patent Literature 1.

In LTE, a predetermined time interval is specified as a unit of time inwhich data transmission is performed. Such a time interval is referredto as a transmission time interval (TTI). For example, the TTI is onemillisecond, and in this case, one TTI corresponds to one sub framelength. The base station device and the terminal device performtransmission and reception of the physical channel and/or the physicalsignal on the basis of the TTI. The details of the TTI are disclosed inNon-Patent Literature 2.

Further, the TTI is used as a unit specifying a data transmissionprocedure. For example, in the data transmission procedure, a hybridautomatic repeat request-acknowledgment (HARQ-ACK) report indicatingwhether or not received data has been correctly received is transmittedafter a period of time specified as an integer multiple of the TTI afterdata is received. Therefore, a period of time (delay or latency)necessary for data transmission is decided depending on the TTI. Such adata transmission procedure is disclosed in Non-Patent Literature 3.

CITATION LIST Non-Patent Literature

Non-Patent Literature 1: 3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; Evolved Universal TerrestrialRadio Access (E-UTRA); Physical Channels and Modulation (Release 12),3GPP TS 36.211 V12.7.0 (2015-09).

Non-Patent Literature 2: 3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; Evolved Universal TerrestrialRadio Access (E-UTRA) and Evolved Universal Terrestrial Radio AccessNetwork (E-UTRAN); Overall description; Stage 2 (Release 12), 3GPP TS36.300 V12.7.0 (2015-09).

Non-Patent Literature 3: 3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; Evolved Universal TerrestrialRadio Access (E-UTRA); Physical layer procedures (Release 12), 3GPP TS36.213 V12.7.0 (2015-09).

DISCLOSURE OF INVENTION Technical Problem

In LTE, only one millisecond is specified as the TTI, and the physicalchannel and the physical signal are specified on the basis of the TTI of1 msec. Further, a period of time necessary for data transmission is anintegral multiple of 1 millisecond. For this reason, in a use case inwhich the period of time necessary for data transmission is important, asize (length) of the TTI affects a characteristic. Further, in a case inwhich a plurality of physical resources are consecutively allocated tothe terminal device in such a use case in order to reduce the period oftime necessary for data transmission, transmission efficiency of theentire system greatly deteriorates.

The present disclosure was made in light of the above problem, and it isan object to provide a base station device, a terminal device, acommunication system, a communication method, and an integrated circuit,which are capable of improving the transmission efficiency of the entiresystem in consideration of the period of time necessary for datatransmission in a communication system in which a base station deviceand a terminal device communicate with each other.

Solution to Problem

According to the present disclosure, there is provided a terminal devicethat communicates with a base station device, including: a higher layerprocessing unit configured to set an STTI channel setting throughsignaling of a higher layer from the base station device; and areceiving unit configured to receive a first PDSCH in a case in whichthe STTI channel setting is not set and receive a second PDSCH in a casein which the STTI channel setting is set. The first PDCCH is mapped toone or more resource blocks, the second PDCCH is mapped to one or moresub resource blocks, and the second PDSCH is demodulated using areference signal mapped to a symbol including the sub resource block ora resource element before the symbol.

In addition, according to the present disclosure, there is provided abase station device that communicates with a terminal device, including:a higher layer processing unit configured to set an STTI channel settingin the terminal device through signaling of a higher layer; and atransmitting unit configured to transmit a first PDSCH in a case inwhich the STTI channel setting is not set and transmit a second PDSCH ina case in which the STTI channel setting is set. The first PDCCH ismapped to one or more resource blocks, the second PDCCH is mapped to oneor more sub resource blocks, and the second PDSCH is demodulated using areference signal mapped to a symbol including the sub resource block ora resource element before the symbol.

In addition, according to the present disclosure, there is provided acommunication method used in a terminal device that communicates with abase station device, including: a step of setting an STTI channelsetting through signaling of a higher layer from the base stationdevice; and a step of receiving a first PDSCH in a case in which theSTTI channel setting is not set and receiving a second PDSCH in a casein which the STTI channel setting is set. The first PDCCH is mapped toone or more resource blocks, the second PDCCH is mapped to one or moresub resource blocks, and the second PDSCH is demodulated using areference signal mapped to a symbol including the sub resource block ora resource element before the symbol.

In addition, according to the present disclosure, there is provided acommunication method used in a base station device that communicateswith a terminal device, including: a step of setting an STTI channelsetting in the terminal device through signaling of a higher layer; anda step of transmitting a first PDSCH in a case in which the STTI channelsetting is not set and transmitting a second PDSCH in a case in whichthe STTI channel setting is set. The first PDCCH is mapped to one ormore resource blocks, the second PDCCH is mapped to one or more subresource blocks, and the second PDSCH is demodulated using a referencesignal mapped to a symbol including the sub resource block or a resourceelement before the symbol.

Advantageous Effects of Invention

As described above, according to the present disclosure, it is possibleto improve the transmission efficiency in the wireless communicationsystem in which the base station device and the terminal devicecommunicate with each other.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a downlink sub frame ofthe present embodiment.

FIG. 2 is a diagram illustrating an example of an uplink sub frame ofthe present embodiment.

FIG. 3 is a schematic block diagram illustrating a configuration of abase station device 1 of the present embodiment.

FIG. 4 is a schematic block diagram illustrating a configuration of aterminal device 2 of the present embodiment.

FIG. 5 is a diagram illustrating an example of downlink resource elementmapping in the present embodiment.

FIG. 6 is a diagram illustrating an example of a TTI in the presentembodiment.

FIG. 7 is a diagram illustrating an example of a TTI in the presentembodiment.

FIG. 8 is a diagram illustrating an example of a set of SPDSCHcandidates.

FIG. 9 is a diagram illustrating an example of SPDSCH transmission in abase station device and a HARQ-ACK report in a terminal device.

FIG. 10 is a diagram illustrating an example of SPDSCH transmission in abase station device and a HARQ-ACK report in a terminal device.

FIG. 11 is a flowchart of a terminal device in which STTI setting isperformed.

FIG. 12 is a diagram illustrating an example of operations of a basestation device and a terminal device in a case in which setting relatedto the same SPDSCH is performed in a plurality of terminal devices.

FIG. 13 is a diagram illustrating an example of resource element mappingof an SPDSCH.

FIG. 14 is a diagram illustrating an example of a reference signal usedfor demodulating an SPDSCH in the present embodiment.

FIG. 15 is a diagram illustrating an example of a reference signal usedfor demodulating an SPDSCH in the present embodiment.

FIG. 16 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied.

FIG. 17 is a block diagram illustrating a second example of theschematic configuration of the eNB to which the technology according tothe present disclosure may be applied.

FIG. 18 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology according tothe present disclosure may be applied.

FIG. 19 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Wireless Communication System in the Present Embodiment

In the present embodiment, a wireless communication system includes atleast a base station device 1 and a terminal device 2. The base stationdevice 1 can accommodate multiple terminal devices. The base stationdevice 1 can be connected with another base station device by means ofan X2 interface. Further, the base station device 1 can be connected toan evolved packet core (EPC) by means of an S1 interface. Further, thebase station device 1 can be connected to a mobility management entity(MME) by means of an S1-MME interface and can be connected to a servinggateway (S-GW) by means of an S1-U interface. The S1 interface supportsmany-to-many connection between the MME and/or the S-GW and the basestation device 1.

Frame Configuration in Present Embodiment

In the present embodiment, a radio frame configured with 10 ms(milliseconds) is specified. Each radio frame includes two half frames.A time interval of the half frame is 5 ms. Each half frame includes 5sub frames. The time interval of the sub frame is 1 ms and is defined bytwo successive slots. The time interval of the slot is 0.5 ms. An i-thsub frame in the radio frame includes a (2×i)-th slot and a (2×i+1)-thslot. In other words, 10 sub frames are specified in each of the radioframes.

The sub frame includes a downlink sub frame (a first sub frame), anuplink sub frame (a second sub frame), a special sub frame (a third subframe), and the like.

The downlink sub frame is a sub frame reserved for downlinktransmission. The uplink sub frame is a sub frame reserved for uplinktransmission. The special sub frame includes three fields. The threefields are a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), andan Uplink Pilot Time Slot (UpPTS). A total length of DwPTS, GP, andUpPTS is 1 ms. The DwPTS is a field reserved for downlink transmission.The UpPTS is a field reserved for uplink transmission. The GP is a fieldin which downlink transmission and uplink transmission are notperformed. Further, the special sub frame may include only the DwPTS andthe GP or may include only the GP and the UpPTS. The special sub frameis placed between the downlink sub frame and the uplink sub frame in TDDand used to perform switching from the downlink sub frame to the uplinksub frame.

A single radio frame includes a downlink sub frame, an uplink sub frame,and/or a special sub frame. Further, a single radio frame may includeonly a downlink sub frame, an uplink sub frame, or a special sub frame.

A plurality of radio frame configurations are supported. The radio frameconfiguration is specified by the frame configuration type. The frameconfiguration type 1 can be applied only to FDD. The frame configurationtype 2 can be applied only to TDD. The frame configuration type 3 can beapplied only to an operation of a licensed assisted access (LAA)secondary cell.

In the frame configuration type 2, a plurality of uplink-downlinkconfigurations are specified. In the uplink-downlink configuration, eachof 10 sub frames in one radio frame corresponds to one of the downlinksub frame, the uplink sub frame, and the special sub frame. The subframe 0, the sub frame 5 and the DwPTS are constantly reserved fordownlink transmission. The UpPTS and the sub frame just after thespecial sub frame are constantly reserved for uplink transmission.

In the frame configuration type 3, 10 sub frames in one radio frame arereserved for downlink transmission. The terminal device 2 treats eachsub frame as an empty sub frame. Unless a predetermined signal, channeland/or downlink transmission is detected in a certain sub frame, theterminal device 2 assumes that there is no signal and/or channel in thesub frame. The downlink transmission is exclusively occupied by one ormore consecutive sub frames. The first sub frame of the downlinktransmission may be started from any one in that sub frame. The last subframe of the downlink transmission may be either completely exclusivelyoccupied or exclusively occupied by a time interval specified in theDwPTS.

Further, in the frame configuration type 3, 10 sub frames in one radioframe may be reserved for uplink transmission. Further, each of 10 subframes in one radio frame may correspond to any one of the downlink subframe, the uplink sub frame, and the special sub frame.

The base station device 1 may transmit a PCFICH, a PHICH, a PDCCH, anEPDCCH, a PDSCH, a synchronization signal, and a downlink referencesignal in the DwPTS of the special sub frame. The base station device 1can restrict transmission of a PBCH in the DwPTS of the special subframe. The terminal device 2 may transmit a PRACH and an SRS in theUpPTS of the special sub frame. In other words, the terminal device 2can restrict transmission of a PUCCH, a PUSCH, and a DMRS in the UpPTSof the special sub frame.

FIG. 1 is a diagram illustrating an example of the downlink sub frame ofthe present embodiment. The diagram illustrated in FIG. 1 is alsoreferred to as a downlink resource grid. The base station device 1 cantransmit a downlink physical channel and/or a downlink physical signalin the downlink sub frame from the base station device 1 to the terminaldevice 2.

The downlink physical channel includes a physical broadcast channel(PBCH), a physical control format indicator channel (PCFICH), a physicalhybrid automatic repeat request indicator channel (PHICH), a physicaldownlink control channel (PDCCH), an enhanced physical downlink controlchannel (EPDCCH), a physical downlink shared channel (PDSCH), a physicalmulticast channel (PMCH), and the like. The downlink physical signalincludes a synchronization signal (SS), a reference signal (RS), adiscovery signal (DS), and the like. In FIG. 1, regions of the PDSCH andthe PDCCH are illustrated for simplicity.

The synchronization signal includes a primary synchronization signal(PSS), a secondary synchronization signal (SSS), and the like. Thereference signal in the downlink includes a cell-specific referencesignal (CRS), a UE-specific reference signal associated with the PDSCH(PDSCH-DMRS:), a demodulation reference signal associated with theEPDCCH (EPDCCH-DMRS), a positioning reference signal (PRS), a channelstate information (CSI) reference signal (CSI-RS), a tracking referencesignal (TRS), and the like. The PDSCH-DMRS is also referred to as a URSassociated with the PDSCH or referred to simply as a URS. TheEPDCCH-DMRS is also referred to as a DMRS associated with the EPDCCH orreferred to simply as DMRS. The PDSCH-DMRS and the EPDCCH-DMRS are alsoreferred to simply as a DL-DMRS or a downlink demodulation referencesignal. The CSI-RS includes a non-zero power CSI-RS (NZP CSI-RS).Further, the downlink resources include a zero power CSI-RS (ZP CSI-RS),a channel state information-interference measurement (CSI-IM), and thelike.

FIG. 2 is a diagram illustrating an example of the uplink sub frame ofthe present embodiment. The diagram illustrated in FIG. 2 is alsoreferred to as an uplink resource grid. The terminal device 2 cantransmit an uplink physical channel and/or an uplink physical signal inthe uplink sub frame from the terminal device 2 to the base stationdevice 1. The uplink physical channel includes a physical uplink sharedchannel (PUSCH), a physical uplink control channel (PUCCH), a physicalrandom access channel (PRACH), and the like. The uplink physical signalincludes a reference signal (RS).

The reference signal in the uplink includes an uplink demodulationsignal (UL-DMRS), a sounding reference signal (SRS), and the like. TheUL-DMRS is associated with transmission of the PUSCH or the PUCCH. TheSRS is not associated with transmission of the PUSCH or the PUCCH.

The downlink physical channel and the downlink physical signal arereferred to collectively as a downlink signal. The uplink physicalchannel and the uplink physical signal are referred to collectively asan uplink signal. The downlink physical channel and the uplink physicalchannel are referred to collectively as a physical channel. The downlinkphysical signal and the uplink physical signal are referred tocollectively as a physical signal.

The BCH, the MCH, the UL-SCH, and the DL-SCH are transport channels.

The channel used in the medium access control (MAC) layer is referred toas a transport channel. A unit of the transport channel used in the MAClayer is also referred to as a transport block (TB) or a MAC protocoldata unit (MAC PDU). In the MAC layer, control of a hybrid automaticrepeat request (HARQ) is performed for each transport block. Thetransport block is a unit of data that the MAC layer transfers(delivers) to the physical layer. In the physical layer, the transportblock is mapped to a codeword, and an encoding process is performed foreach codeword.

Physical Resources in Present Embodiment

In the present embodiment, one slot is defined by a plurality ofsymbols. The physical signal or the physical channel transmitted in eachof the slots is represented by a resource grid. In the downlink, theresource grid is defined by a plurality of sub carriers in a frequencydirection and a plurality of OFDM symbols in a time direction. In theuplink, the resource grid is defined by a plurality of sub carriers inthe frequency direction and a plurality of SC-FDMA symbols in the timedirection. The number of sub carriers or the number of resource blocksmay be decided depending on a bandwidth of a cell. The number of symbolsin one slot is decided by a type of cyclic prefix (CP). The type of CPis a normal CP or an extended CP. In the normal CP, the number of OFDMsymbols or SC-FDMA symbols constituting one slot is 7. In the extendedCP, the number of OFDM symbols or SC-FDMA symbols constituting one slotis 6. Each element in the resource grid is referred to as a resourceelement. The resource element is identified using an index (number) of asub carrier and an index (number) of a symbol. Further, in thedescription of the present embodiment, the OFDM symbol or SC-FDMA symbolis also referred to simply as a symbol.

The resource blocks are used for mapping to resource elements of acertain physical channel (the PDSCH, the PUSCH, or the like). Theresource blocks include virtual resource blocks and physical resourceblocks. A certain physical channel is mapped to a virtual resourceblock. The virtual resource blocks are mapped to physical resourceblocks. One physical resource block is defined by a predetermined numberof consecutive symbols in the time domain. One physical resource blockis defined from a predetermined number of consecutive sub carriers inthe frequency domain. The number of symbols and the number of subcarriers in one physical resource block are decided on the basis of aparameter set in accordance with a type of CP, a sub carrier interval,and/or a higher layer in the cell. For example, in a case in which thetype of CP is the normal CP, and the sub carrier interval is 15 kHz, thenumber of symbols in one physical resource block is 7, and the number ofsub carriers is 12. In this case, one physical resource block includes(7×12) resource elements. The physical resource blocks are numbered from0 in the frequency domain. Further, two resource blocks in one sub framecorresponding to the same physical resource block number are defined asa physical resource block pair (a PRB pair or an RB pair).

A resource element group (REG) is used to define mapping of the resourceelement and the control channel. For example, the REG is used formapping of the PDCCH, the PHICH, or the PCFICH. The REG is constitutedby four consecutive resource elements which are in the same OFDM symboland not used for the CRS in the same resource block. Further, the REG isconstituted by first to fourth OFDM symbols in a first slot in a certainsub frame.

An enhanced resource element group (EREG) is used to define mapping ofthe resource elements and the enhanced control channel. For example, theEREG is used for mapping of the EPDCCH. One resource block pair isconstituted by 16 EREGs. Each EREG is assigned a number of 0 to 15 foreach resource block pair. Each EREG is constituted by 9 resourceelements excluding resource elements used for the DM-RS associated withthe EPDCCH in one resource block pair.

Antenna Port in Present Embodiment

An antenna port is defined so that a propagation channel carrying acertain symbol can be inferred from a propagation channel carryinganother symbol in the same antenna port. For example, different physicalresources in the same antenna port can be assumed to be transmittedthrough the same propagation channel. In other words, for a symbol in acertain antenna port, it is possible to estimate and demodulate apropagation channel in accordance with the reference signal in theantenna port. Further, there is one resource grid for each antenna port.The antenna port is defined by the reference signal. Further, eachreference signal can define a plurality of antenna ports.

In a case in which two antenna ports satisfy a predetermined condition,the two antenna ports can be regarded as being a quasi co-location(QCL). The predetermined condition is that a wide area characteristic ofa propagation channel carrying a symbol in one antenna port can beinferred from a propagation channel carrying a symbol in another antennaport. The wide area characteristic includes a delay dispersion, aDoppler spread, a Doppler shift, an average gain, and/or an averagedelay.

Downlink Physical Channel in Present Embodiment

The PBCH is used to broadcast a master information block (MIB) which isbroadcast information specific to a serving cell of the base stationdevice 1. The PBCH is transmitted only through the sub frame 0 in theradio frame. The MIB can be updated at intervals of 40 ms. The PBCH isrepeatedly transmitted with a cycle of 10 ms. Specifically, initialtransmission of the MTB is performed in the sub frame 0 in the radioframe satisfying a condition that a remainder obtained by dividing asystem frame number (SFN) by 4 is 0, and retransmission (repetition) ofthe MIB is performed in the sub frame 0 in all the other radio frames.The SFN is a radio frame number (system frame number). The MIB is systeminformation. For example, the MIB includes information indicating theSFN.

The PCFICH is used to transmit information related to the number of OFDMsymbols used for transmission of the PDCCH. A region indicated by PCFICHis also referred to as a PDCCH region. The information transmittedthrough the PCFICH is also referred to as a control format indicator(CFI).

The PHICH is used to transmit an HARQ-ACK (an HARQ indicator, HARQfeedback, and response information) indicating ACKnowledgment (ACK) ornegative ACKnowledgment (NACK) of uplink data (an uplink shared channel(UL-SCH)) received by the base station device 1. For example, in a casein which the HARQ-ACK indicating ACK is received, corresponding uplinkdata is not retransmitted. For example, in a case in which the terminaldevice 2 receives the HARQ-ACK indicating NACK, the terminal device 2retransmits corresponding uplink data through a predetermined uplink subframe. A certain PHICH transmits the HARQ-ACK for certain uplink data.The base station device 1 transmits each HARQ-ACK to a plurality ofpieces of uplink data included in the same PUSCH using a plurality ofPHICHs.

The PDCCH and the EPDCCH are used to transmit downlink controlinformation (DCI). Mapping of an information bit of the downlink controlinformation is defined as a DCI format. The downlink control informationincludes a downlink grant and an uplink grant. The downlink grant isalso referred to as a downlink assignment or a downlink allocation.

The PDCCH is transmitted by a set of one or more consecutive controlchannel elements (CCEs). The CCE includes 9 resource element groups(REGs). An REG includes 4 resource elements. In a case in which thePDCCH is constituted by n consecutive CCEs, the PDCCH starts with a CCEsatisfying a condition that a remainder after dividing an index (number)i of the CCE by n is 0.

The EPDCCH is transmitted by a set of one or more consecutive enhancedcontrol channel elements (ECCEs). The ECCE is constituted by a pluralityof enhanced resource element groups (EREGs).

The downlink grant is used for scheduling of the PDSCH in a certaincell. The downlink grant is used for scheduling of the PDSCH in the samesub frame as a sub frame in which the downlink grant is transmitted. Theuplink grant is used for scheduling of the PUSCH in a certain cell. Theuplink grant is used for scheduling of a single PUSCH in a fourth subframe from a sub frame in which the uplink grant is transmitted orlater.

A cyclic redundancy check (CRC) parity bit is added to the DCI. The CRCparity bit is scrambled using a radio network temporary identifier(RNTI). The RNTI is an identifier that can be specified or set inaccordance with a purpose of the DCI or the like. The RNTI is anidentifier specified in a specification in advance, an identifier set asinformation specific to a cell, an identifier set as informationspecific to the terminal device 2, or an identifier set as informationspecific to a group to which the terminal device 2 belongs. For example,in monitoring of the PDCCH or the EPDCCH, the terminal device 2descrambles the CRC parity bit added to the DCI with a predeterminedRNTI and identifies whether or not the CRC is correct. In a case inwhich the CRC is correct, the DCI is understood to be a DCI for theterminal device 2.

The PDSCH is used to transmit downlink data (a downlink shared channel(DL-SCH)). Further, the PDSCH is also used to transmit controlinformation of a higher layer.

The PMCH is used to transmit multicast data (a multicast channel (MCH)).

In the PDCCH region, a plurality of PDCCHs may be multiplexed accordingto frequency, time, and/or space. In the EPDCCH region, a plurality ofEPDCCHs may be multiplexed according to frequency, time, and/or space.In the PDSCH region, a plurality of PDSCHs may be multiplexed accordingto frequency, time, and/or space. The PDCCH, the PDSCH, and/or theEPDCCH may be multiplexed according to frequency, time, and/or space.

Downlink Physical Signal in Present Embodiment

A synchronization signal is used for the terminal device 2 to obtaindownlink synchronization in the frequency domain and/or the time domain.The synchronization signal includes a primary synchronization signal(PSS) and a secondary synchronization signal (SSS). The synchronizationsignal is placed in a predetermined sub frame in the radio frame. Forexample, in the TDD scheme, the synchronization signal is placed in thesub frames 0, 1, 5, and 6 in the radio frame. In the FDD scheme, thesynchronization signal is placed in the sub frames 0 and 5 in the radioframe.

The PSS may be used for coarse frame/timing synchronization(synchronization in the time domain) or cell group identification. TheSSS may be used for more accurate frame timing synchronization or cellidentification. In other words, frame timing synchronization and cellidentification can be performed using the PSS and the SSS.

The downlink reference signal is used for the terminal device 2 toperform propagation path estimation of the downlink physical channel,propagation path correction, calculation of downlink channel stateinformation (CSI), and/or measurement of positioning of the terminaldevice 2.

The CRS is transmitted in the entire band of the sub frame. The CRS isused for receiving (demodulating) the PBCH, the PDCCH, the PHICH, thePCFICH, and the PDSCH. The CRS may be used for the terminal device 2 tocalculate the downlink channel state information. The PBCH, the PDCCH,the PHICH, and the PCFICH are transmitted through the antenna port usedfor transmission of the CRS. The CRS supports the antenna portconfigurations of 1, 2, or 4. The CRS is transmitted through one or moreof the antenna ports 0 to 3.

The URS associated with the PDSCH is transmitted through a sub frame anda band used for transmission of the PDSCH with which the URS isassociated. The URS is used for demodulation of the PDSCH to which theURS is associated. The URS associated with the PDSCH is transmittedthrough one or more of the antenna ports 5 and 7 to 14.

The PDSCH is transmitted through an antenna port used for transmissionof the CRS or the URS on the basis of the transmission mode and the DCIformat. A DCI format 1A is used for scheduling of the PDSCH transmittedthrough an antenna port used for transmission of the CRS. A DCI format2D is used for scheduling of the PDSCH transmitted through an antennaport used for transmission of the URS.

The DMRS associated with the EPDCCH is transmitted through a sub frameand a band used for transmission of the EPDCCH to which the DMRS isassociated. The DMRS is used for demodulation of the EPDCCH with whichthe DMRS is associated. The EPDCCH is transmitted through an antennaport used for transmission of the DMRS. The DMRS associated with theEPDCCH is transmitted through one or more of the antenna ports 107 to114.

The CSI-RS is transmitted through a set sub frame. The resources inwhich the CSI-RS is transmitted are set by the base station device 1.The CSI-RS is used for the terminal device 2 to calculate the downlinkchannel state information. The terminal device 2 performs signalmeasurement (channel measurement) using the CSI-RS. The CSI-RS supportssetting of some or all of the antenna ports 1, 2, 4, 8, 12, 16, 24, and32. The CSI-RS is transmitted through one or more of the antenna ports15 to 46. Further, an antenna port to be supported may be decided on thebasis of a terminal device capability of the terminal device 2, settingof an RRC parameter, and/or a transmission mode to be set.

Resources of the ZP CSI-RS are set by a higher layer. Resources of theZP CSI-RS are transmitted with zero output power. In other words, theresources of the ZP CSI-RS are not transmitted. The ZP PDSCH and theEPDCCH are not transmitted in the resources in which the ZP CSI-RS isset. For example, the resources of the ZP CSI-RS are used for a neighborcell to transmit the NZP CSI-RS. Further, for example, the resources ofthe ZP CSI-RS are used to measure the CSI-IM.

Resources of the CSI-IM are set by the base station device 1. Theresources of the CSI-IM are resources used for measuring interference inCSI measurement. The resources of the CSI-IM can be set to overlap someof the resources of the ZP CSI-RS. For example, in a case in which theresources of the CSI-IM are set to overlap some of the resources of theZP CSI-RS, a signal from a cell performing the CSI measurement is nottransmitted in the resources. In other words, the base station device 1does not transmit the PDSCH, the EPDCCH, or the like in the resourcesset by the CSI-IM. Therefore, the terminal device 2 can perform the CSImeasurement efficiently.

The MBSFN RS is transmitted in the entire band of the sub frame used fortransmission of the PMCH. The MBSFN RS is used for demodulation of thePMCH. The PMCH is transmitted through an antenna port used fortransmission of the MBSFN RS. The MBSFN RS is transmitted through theantenna port 4.

The PRS is used for the terminal device 2 to measure positioning of theterminal device 2. The PRS is transmitted through the antenna port 6.

The TRS can be mapped only to predetermined sub frames. For example, theTRS is mapped to the sub frames 0 and 5. Further, the TRS can use aconfiguration similar to a part or all of the CRS. For example, in eachresource block, a position of a resource element to which the TRS ismapped can be caused to coincide with a position of a resource elementto which the CRS of the antenna port 0 is mapped. Further, a sequence(value) used for the TRS can be decided on the basis of information setthrough the PBCH, the PDCCH, the EPDCCH, or the PDSCH (RRC signaling). Asequence (value) used for the TRS can be decided on the basis of aparameter such as a cell ID (for example, a physical layer cellidentifier), a slot number, or the like. A sequence (value) used for theTRS can be decided by a method (formula) different from that of asequence (value) used for the CRS of the antenna port 0.

Uplink Physical Signal in Present Embodiment

The PUCCH is a physical channel used for transmitting uplink controlinformation (UCI). The uplink control information includes downlinkchannel state information (CSI), a scheduling request (SR) indicating arequest for PUSCH resources, and a HARQ-ACK to downlink data (atransport block (TB) or a downlink-shared channel (DL-SCH)). TheHARQ-ACK is also referred to as ACK/NACK, HARQ feedback, or responseinformation. Further, the HARQ-ACK to downlink data indicates ACK, NACK,or DTX.

The PUSCH is a physical channel used for transmitting uplink data(uplink-shared channel (UL-SCH)). Further, the PUSCH may be used totransmit the HARQ-ACK and/or the channel state information together withuplink data. Further, the PUSCH may be used to transmit only the channelstate information or only the HARQ-ACK and the channel stateinformation.

The PRACH is a physical channel used for transmitting a random accesspreamble. The PRACH can be used for the terminal device 2 to obtainsynchronization in the time domain with the base station device 1.Further, the PRACH is also used to indicate an initial connectionestablishment procedure (process), a handover procedure, a connectionre-establishment procedure, synchronization (timing adjustment) foruplink transmission, and/or a request for PUSCH resources.

In the PUCCH region, a plurality of PUCCHs are frequency, time, space,and/or code multiplexed. In the PUSCH region, a plurality of PUSCHs maybe frequency, time, space, and/or code multiplexed. The PUCCH and thePUSCH may be frequency, time, space, and/or code multiplexed. The PRACHmay be placed over a single sub frame or two sub frames. A plurality ofPRACHs may be code-multiplexed.

Uplink Physical Channel in Present Embodiment

The uplink DMRS is associated with transmission of the PUSCH or thePUCCH. The DMRS is time-multiplexed with the PUSCH or the PUCCH. Thebase station device 1 may use the DMRS to perform the propagation pathcorrection of the PUSCH or the PUCCH. In the description of the presentembodiment, the transmission of the PUSCH also includes multiplexing andtransmitting the PUSCH and DMRS. In the description of the presentembodiment, the transmission of the PUCCH also includes multiplexing andtransmitting the PUCCH and the DMRS. Further, the uplink DMRS is alsoreferred to as an UL-DMRS. The SRS is not associated with thetransmission of the PUSCH or the PUCCH. The base station device 1 mayuse the SRS to measure the uplink channel state.

The SRS is transmitted using the last SC-FDMA symbol in the uplink subframe. In other words, the SRS is placed in the last SC-FDMA symbol inthe uplink sub frame. The terminal device 2 can restrict simultaneoustransmission of the SRS, the PUCCH, the PUSCH, and/or the PRACH in acertain SC-FDMA symbol of a certain cell. The terminal device 2 cantransmit the PUSCH and/or the PUCCH using the SC-FDMA symbol excludingthe last SC-FDMA symbol in a certain uplink sub frame of a certain cellin the uplink sub frame and transmit the SRS using the last SC-FDMAsymbol in the uplink sub frame. In other words, the terminal device 2can transmit the SRS, the PUSCH, and the PUCCH in a certain uplink subframe of a certain cell.

In the SRS, a trigger type 0 SRS and a trigger type 1 SRS are defined asSRSs having different trigger types. The trigger type 0 SRS istransmitted in a case in which a parameter related to the trigger type 0SRS is set by signaling of a higher layer. The trigger type 1 SRS istransmitted in a case in which a parameter related to the trigger type 1SRS is set by signaling of the higher layer, and transmission isrequested by an SRS request included in the DCI format 0, 1A, 2B, 2C,2D, or 4. Further, the SRS request is included in both FDD and TDD forthe DCI format 0, 1A, or 4 and included only in TDD for the DCI format2B, 2C, or 2D. In a case in which the transmission of the trigger type 0SRS and the transmission of the trigger type 1 SRS occur in the same subframe of the same serving cell, a priority is given to the transmissionof the trigger type 1 SRS.

Configuration Example of Base Station Device 1 in Present Embodiment

FIG. 3 is a schematic block diagram illustrating a configuration of thebase station device 1 of the present embodiment. As illustrated in FIG.3, the base station device 1 includes a higher layer processing unit101, a control unit 103, a receiving unit 105, a transmitting unit 107,and a transceiving antenna 109. Further, the receiving unit 105 includesa decoding unit 1051, a demodulating unit 1053, a demultiplexing unit1055, a wireless receiving unit 1057, and a channel measuring unit 1059.Further, the transmitting unit 107 includes an encoding unit 1071, amodulating unit 1073, a multiplexing unit 1075, a wireless transmittingunit 1077, and a downlink reference signal generating unit 1079.

The higher layer processing unit 101 performs processes of a mediumaccess control (MAC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer, and a radio resource control(RRC) layer. Further, the higher layer processing unit 101 generatescontrol information to control the receiving unit 105 and thetransmitting unit 107 and outputs the control information to the controlunit 103.

The control unit 103 controls the receiving unit 105 and thetransmitting unit 107 on the basis of the control information from thehigher layer processing unit 101. The control unit 103 generates controlinformation to be transmitted to the higher layer processing unit 101and outputs the control information to the higher layer processing unit101. The control unit 103 receives a decoded signal from the decodingunit 1051 and a channel estimation result from the channel measuringunit 1059. The control unit 103 outputs a signal to be encoded to theencoding unit 1071. Further, the control unit 103 may be used to controlthe whole or a part of the base station device 1.

The higher layer processing unit 101 performs a process and managementrelated to radio resource control, sub frame setting, schedulingcontrol, and/or CSI report control. The process and the management inthe higher layer processing unit 101 are performed for each terminaldevice or in common to terminal devices connected to the base stationdevice. The process and the management in the higher layer processingunit 101 may be performed only by the higher layer processing unit 101or may be acquired from a higher node or another base station device.

In the radio resource control in the higher layer processing unit 101,generation and/or management of downlink data (transport block), systeminformation, an RRC message (RRC parameter), and/or a MAC controlelement (CE) are performed.

In a sub frame setting in the higher layer processing unit 101,management of a sub frame setting, a sub frame pattern setting, anuplink-downlink setting, an uplink reference UL-DL setting, and/or adownlink reference UL-DL setting is performed. Further, the sub framesetting in the higher layer processing unit 101 is also referred to as abase station sub frame setting. Further, the sub frame setting in thehigher layer processing unit 101 can be decided on the basis of anuplink traffic volume and a downlink traffic volume. Further, the subframe setting in the higher layer processing unit 101 can be decided onthe basis of a scheduling result of scheduling control in the higherlayer processing unit 101.

In the scheduling control in the higher layer processing unit 101, afrequency and a sub frame to which the physical channel (the PDSCH andthe PUSCH) is allocated, a coding rate, a modulation scheme, andtransmission power of the physical channels (the PDSCH and the PUSCH),and the like are decided on the basis of the received channel stateinformation, an estimation value, a channel quality, or the like of apropagation path input from the channel measuring unit 1059, and thelike. For example, the control unit 103 generates the controlinformation (DCI format) on the basis of the scheduling result of thescheduling control in the higher layer processing unit 101.

In the CSI report control in the higher layer processing unit 101, theCSI report of the terminal device 2 is controlled. For example, asettings related to the CSI reference resources assumed to calculate theCSI in the terminal device 2 is controlled.

Under the control from the control unit 103, the receiving unit 105receives a signal transmitted from the terminal device 2 via thetransceiving antenna 109, performs a reception process such asdemultiplexing, demodulation, and decoding, and outputs informationwhich has undergone the reception process to the control unit 103.Further, the reception process in the receiving unit 105 is performed onthe basis of a setting which is specified in advance or a settingnotified from the base station device 1 to the terminal device 2.

The wireless receiving unit 1057 performs conversion into anintermediate frequency (down conversion), removal of an unnecessaryfrequency component, control of an amplification level such that asignal level is appropriately maintained, quadrature demodulation basedon an in-phase component and a quadrature component of a receivedsignal, conversion from an analog signal into a digital signal, removalof a guard interval (GI), and/or extraction of a signal in the frequencydomain by fast Fourier transform (FFT) on the uplink signal received viathe transceiving antenna 109.

The demultiplexing unit 1055 separates the uplink channel such as thePUCCH or the PUSCH and/or uplink reference signal from the signal inputfrom the wireless receiving unit 1057. The demultiplexing unit 1055outputs the uplink reference signal to the channel measuring unit 1059.The demultiplexing unit 1055 compensates the propagation path for theuplink channel from the estimation value of the propagation path inputfrom the channel measuring unit 1059.

The demodulating unit 1053 demodulates the reception signal for themodulation symbol of the uplink channel using a modulation scheme suchas binary phase shift keying (BPSK), quadrature phase shift keying(QPSK), 16 quadrature amplitude modulation (QAM), 64 QAM, or 256 QAM.The demodulating unit 1053 performs separation and demodulation of aMIMO multiplexed uplink channel.

The decoding unit 1051 performs a decoding process on encoded bits ofthe demodulated uplink channel. The decoded uplink data and/or uplinkcontrol information are output to the control unit 103. The decodingunit 1051 performs a decoding process on the PUSCH for each transportblock.

The channel measuring unit 1059 measures the estimation value, a channelquality, and/or the like of the propagation path from the uplinkreference signal input from the demultiplexing unit 1055, and outputsthe estimation value, a channel quality, and/or the like of thepropagation path to the demultiplexing unit 1055 and/or the control unit103. For example, the estimation value of the propagation path forpropagation path compensation for the PUCCH or the PUSCH is measuredthrough the UL-DMRS, and an uplink channel quality is measured throughthe SRS.

The transmitting unit 107 carries out a transmission process such asencoding, modulation, and multiplexing on downlink control informationand downlink data input from the higher layer processing unit 101 underthe control of the control unit 103. For example, the transmitting unit107 generates and multiplexes the PHICH, the PDCCH, the EPDCCH, thePDSCH, and the downlink reference signal and generates a transmissionsignal. Further, the transmission process in the transmitting unit 107is performed on the basis of a setting which is specified in advance, asetting notified from the base station device 1 to the terminal device2, or a setting notified through the PDCCH or the EPDCCH transmittedthrough the same sub frame.

The encoding unit 1071 encodes the HARQ indicator (HARQ-ACK), thedownlink control information, and the downlink data input from thecontrol unit 103 using a predetermined coding scheme such as blockcoding, convolutional coding, turbo coding, or the like. The modulatingunit 1073 modulates the encoded bits input from the encoding unit 1071using a predetermined modulation scheme such as BPSK, QPSK, 16 QAM, 64QAM, or 256 QAM. The downlink reference signal generating unit 1079generates the downlink reference signal on the basis of a physical cellidentification (PCI), an RRC parameter set in the terminal device 2, andthe like. The multiplexing unit 1075 multiplexes a modulated symbol andthe downlink reference signal of each channel and arranges resultingdata in a predetermined resource element.

The wireless transmitting unit 1077 performs processes such asconversion into a signal in the time domain by inverse fast Fouriertransform (IFFT), addition of the guard interval, generation of abaseband digital signal, conversion in an analog signal, quadraturemodulation, conversion from a signal of an intermediate frequency into asignal of a high frequency (up conversion), removal of an extrafrequency component, and amplification of power on the signal from themultiplexing unit 1075, and generates a transmission signal. Thetransmission signal output from the wireless transmitting unit 1077 istransmitted through the transceiving antenna 109.

Configuration Example of Base Station Device 1 in Present Embodiment

FIG. 4 is a schematic block diagram illustrating a configuration of theterminal device 2 of the present embodiment. As illustrated in FIG. 4,the terminal device 2 includes a higher layer processing unit 201, acontrol unit 203, a receiving unit 205, a transmitting unit 207, and atransceiving antenna 209. Further, the receiving unit 205 includes adecoding unit 2051, a demodulating unit 2053, a demultiplexing unit2055, a wireless receiving unit 2057, and a channel measuring unit 2059.Further, the transmitting unit 207 includes an encoding unit 2071, amodulating unit 2073, a multiplexing unit 2075, a wireless transmittingunit 2077, and an uplink reference signal generating unit 2079.

The higher layer processing unit 201 outputs uplink data (transportblock) to the control unit 203. The higher layer processing unit 201performs processes of a medium access control (MAC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda radio resource control (RRC) layer. Further, the higher layerprocessing unit 201 generates control information to control thereceiving unit 205 and the transmitting unit 207 and outputs the controlinformation to the control unit 203.

The control unit 203 controls the receiving unit 205 and thetransmitting unit 207 on the basis of the control information from thehigher layer processing unit 201. The control unit 203 generates controlinformation to be transmitted to the higher layer processing unit 201and outputs the control information to the higher layer processing unit201. The control unit 203 receives a decoded signal from the decodingunit 2051 and a channel estimation result from the channel measuringunit 2059. The control unit 203 outputs a signal to be encoded to theencoding unit 2071. Further, the control unit 203 may be used to controlthe whole or a part of the terminal device 2.

The higher layer processing unit 201 performs a process and managementrelated to radio resource control, sub frame setting, schedulingcontrol, and/or CSI report control. The process and the management inthe higher layer processing unit 201 are performed on the basis of asetting which is specified in advance and/or a setting based on controlinformation set or notified from the base station device 1. For example,the control information from the base station device 1 includes the RRCparameter, the MAC control element, or the DCI.

In the radio resource control in the higher layer processing unit 201,the setting information in the terminal device 2 is managed. In theradio resource control in the higher layer processing unit 201,generation and/or management of uplink data (transport block), systeminformation, an RRC message (RRC parameter), and/or a MAC controlelement (CE) are performed.

In the sub frame setting in the higher layer processing unit 201, thesub frame setting in the base station device 1 and/or a base stationdevice different from the base station device 1 is managed. The subframe setting includes an uplink or downlink setting for the sub frame,a sub frame pattern setting, an uplink-downlink setting, an uplinkreference UL-DL setting, and/or a downlink reference UL-DL setting.Further, the sub frame setting in the higher layer processing unit 201is also referred to as a terminal sub frame setting.

In the scheduling control in the higher layer processing unit 201,control information for controlling scheduling on the receiving unit 205and the transmitting unit 207 is generated on the basis of the DCI(scheduling information) from the base station device 1.

In the CSI report control in the higher layer processing unit 201,control related to the report of the CSI to the base station device 1 isperformed. For example, in the CSI report control, a setting related tothe CSI reference resources assumed for calculating the CSI by thechannel measuring unit 2059 is controlled. In the CSI report control,resource (timing) used for reporting the CSI is controlled on the basisof the DCI and/or the RRC parameter.

Under the control from the control unit 203, the receiving unit 205receives a signal transmitted from the base station device 1 via thetransceiving antenna 209, performs a reception process such asdemultiplexing, demodulation, and decoding, and outputs informationwhich has undergone the reception process to the control unit 203.Further, the reception process in the receiving unit 205 is performed onthe basis of a setting which is specified in advance or a notificationfrom the base station device 1 or a setting.

The wireless receiving unit 2057 performs conversion into anintermediate frequency (down conversion), removal of an unnecessaryfrequency component, control of an amplification level such that asignal level is appropriately maintained, quadrature demodulation basedon an in-phase component and a quadrature component of a receivedsignal, conversion from an analog signal into a digital signal, removalof a guard interval (GI), and/or extraction of a signal in the frequencydomain by fast Fourier transform (FFT) on the uplink signal received viathe transceiving antenna 209.

The demultiplexing unit 2055 separates the downlink channel such as thePHICH, PDCCH, EPDCCH, or PDSCH, downlink synchronization signal and/ordownlink reference signal from the signal input from the wirelessreceiving unit 2057. The demultiplexing unit 2055 outputs the uplinkreference signal to the channel measuring unit 2059. The demultiplexingunit 2055 compensates the propagation path for the uplink channel fromthe estimation value of the propagation path input from the channelmeasuring unit 2059.

The demodulating unit 2053 demodulates the reception signal for themodulation symbol of the downlink channel using a modulation scheme suchas BPSK, QPSK, 16 QAM, 64 QAM, or 256 QAM. The demodulating unit 2053performs separation and demodulation of a MIMO multiplexed downlinkchannel.

The decoding unit 2051 performs a decoding process on encoded bits ofthe demodulated downlink channel. The decoded downlink data and/ordownlink control information are output to the control unit 203. Thedecoding unit 2051 performs a decoding process on the PDSCH for eachtransport block.

The channel measuring unit 2059 measures the estimation value, a channelquality, and/or the like of the propagation path from the downlinkreference signal input from the demultiplexing unit 2055, and outputsthe estimation value, a channel quality, and/or the like of thepropagation path to the demultiplexing unit 2055 and/or the control unit203. The downlink reference signal used for measurement by the channelmeasuring unit 2059 may be decided on the basis of at least atransmission mode set by the RRC parameter and/or other RRC parameters.For example, the estimation value of the propagation path for performingthe propagation path compensation on the PDSCH or the EPDCCH is measuredthrough the DL-DMRS.

The estimation value of the propagation path for performing thepropagation path compensation on the PDCCH or the PDSCH and/or thedownlink channel for reporting the CSI are measured through the CRS. Thedownlink channel for reporting the CSI is measured through the CSI-RS.The channel measuring unit 2059 calculates a reference signal receivedpower (RSRP) and/or a reference signal received quality (RSRQ) on thebasis of the CRS, the CSI-RS, or the discovery signal, and outputs theRSRP and/or the RSRQ to the higher layer processing unit 201.

The transmitting unit 207 performs a transmission process such asencoding, modulation, and multiplexing on the uplink control informationand the uplink data input from the higher layer processing unit 201under the control of the control unit 203. For example, the transmittingunit 207 generates and multiplexes the uplink channel such as the PUSCHor the PUCCH and/or the uplink reference signal, and generates atransmission signal. Further, the transmission process in thetransmitting unit 207 is performed on the basis of a setting which isspecified in advance or a setting set or notified from the base stationdevice 1.

The encoding unit 2071 encodes the HARQ indicator (HARQ-ACK), the uplinkcontrol information, and the uplink data input from the control unit 203using a predetermined coding scheme such as block coding, convolutionalcoding, turbo coding, or the like. The modulating unit 2073 modulatesthe encoded bits input from the encoding unit 2071 using a predeterminedmodulation scheme such as BPSK, QPSK, 16 QAM, 64 QAM, or 256 QAM. Theuplink reference signal generating unit 2079 generates the uplinkreference signal on the basis of an RRC parameter set in the terminaldevice 2, and the like. The multiplexing unit 2075 multiplexes amodulated symbol and the uplink reference signal of each channel andarranges resulting data in a predetermined resource element.

The wireless transmitting unit 2077 performs processes such asconversion into a signal in the time domain by inverse fast Fouriertransform (IFFT), addition of the guard interval, generation of abaseband digital signal, conversion in an analog signal, quadraturemodulation, conversion from a signal of an intermediate frequency into asignal of a high frequency (up conversion), removal of an extrafrequency component, and amplification of power on the signal from themultiplexing unit 2075, and generates a transmission signal. Thetransmission signal output from the wireless transmitting unit 2077 istransmitted through the transceiving antenna 209.

Signaling of Control Information in Present Embodiment

The base station device 1 and the terminal device 2 can use variousmethods for signaling (notification, broadcasting, or setting) of thecontrol information. The signaling of the control information can beperformed in various layers (layers). The signaling of the controlinformation includes signaling of the physical layer which is signalingperformed through the physical layer, RRC signaling which is signalingperformed through the RRC layer, and MAC signaling which is signalingperformed through the MAC layer. The RRC signaling is dedicated RRCsignaling for notifying the terminal device 2 of the control informationspecific or a common RRC signaling for notifying of the controlinformation specific to the base station device 1. The signaling used bya layer higher than the physical layer such as RRC signaling and MACsignaling is also referred to as signaling of the higher layer.

The RRC signaling is implemented by signaling the RRC parameter. The MACsignaling is implemented by signaling the MAC control element. Thesignaling of the physical layer is implemented by signaling the downlinkcontrol information (DCI) or the uplink control information (UCI). TheRRC parameter and the MAC control element are transmitted using thePDSCH or the PUSCH. The DCI is transmitted using the PDCCH or theEPDCCH. The UCI is transmitted using the PUCCH or the PUSCH. The RRCsignaling and the MAC signaling are used for signaling semi-staticcontrol information and are also referred to as semi-static signaling.The signaling of the physical layer is used for signaling dynamiccontrol information and also referred to as dynamic signaling. The DCIis used for scheduling of the PDSCH or scheduling of the PUSCH. The UCIis used for the CSI report, the HARQ-ACK report, and/or the schedulingrequest (SR).

Details of Downlink Control Information in Present Embodiment

The DCI is notified using the DCI format having a field which isspecified in advance. Predetermined information bits are mapped to thefield specified in the DCI format. The DCI notifies of downlinkscheduling information, uplink scheduling information, sidelinkscheduling information, a request for a non-periodic CSI report, or anuplink transmission power command.

The DCI format monitored by the terminal device 2 is decided inaccordance with the transmission mode set for each serving cell. Inother words, a part of the DCI format monitored by the terminal device 2can differ depending on the transmission mode. For example, the terminaldevice 2 in which a downlink transmission mode 1 is set monitors the DCIformat 1A and the DCI format 1. For example, the terminal device 2 inwhich a downlink transmission mode 4 is set monitors the DCI format 1Aand the DCI format 2. For example, the terminal device 2 in which anuplink transmission mode 1 is set monitors the DCI format 0. Forexample, the terminal device 2 in which an uplink transmission mode 2 isset monitors the DCI format 0 and the DCI format 4.

A control region in which the PDCCH for notifying the terminal device 2of the DCI is placed is not notified of, and the terminal device 2detects the DCI for the terminal device 2 through blind decoding (blinddetection). Specifically, the terminal device 2 monitors a set of PDCCHcandidates in the serving cell. The monitoring indicates that decodingis attempted in accordance with all the DCI formats to be monitored foreach of the PDCCHs in the set. For example, the terminal device 2attempts to decode all aggregation levels, PDCCH candidates, and DCIformats which are likely to be transmitted to the terminal device 2. Theterminal device 2 recognizes the DCI (PDCCH) which is successfullydecoded (detected) as the DCI (PDCCH) for the terminal device 2.

A cyclic redundancy check (CRC) is added to the DCI. The CRC is used forthe DCI error detection and the DCI blind detection. A CRC parity bit(CRC) is scrambled using the RNTI. The terminal device 2 detects whetheror not it is a DCI for the terminal device 2 on the basis of the RNTI.Specifically, the terminal device 2 performs de-scrambling on the bitcorresponding to the CRC using a predetermined RNTI, extracts the CRC,and detects whether or not the corresponding DCI is correct.

The RNTI is specified or set in accordance with a purpose or a use ofthe DCI. The RNTI includes a cell-RNTI (C-RNTI), a semi persistentscheduling C-RNTI (SPS C-RNTI), a system information-RNTI (SI-RNTI), apaging-RNTI (P-RNTI), a random access-RNTI (RA-RNTI), a transmit powercontrol-PUCCH-RNTI (TPC-PUCCH-RNTI), a transmit power control-PUSCH-RNTI(TPC-PUSCH-RNTI), a temporary C-RNTI, a multimedia broadcast multicastservices (MBMS)-RNTI (M-RNTI)), and an eIMTA-RNTI.

The C-RNTI and the SPS C-RNTI are RNTIs which are specific to theterminal device 2 in the base station device 1 (cell), and serve asidentifiers identifying the terminal device 2. The C-RNTI is used forscheduling the PDSCH or the PUSCH in a certain sub frame. The SPS C-RNTIis used to activate or release periodic scheduling of resources for thePDSCH or the PUSCH. A control channel having a CRC scrambled using theSI-RNTI is used for scheduling a system information block (SIB). Acontrol channel with a CRC scrambled using the P-RNTI is used forcontrolling paging. A control channel with a CRC scrambled using theRA-RNTI is used for scheduling a response to the RACH. A control channelhaving a CRC scrambled using the TPC-PUCCH-RNTI is used for powercontrol of the PUCCH. A control channel having a CRC scrambled using theTPC-PUSCH-RNTI is used for power control of the PUSCH. A control channelwith a CRC scrambled using the temporary C-RNTI is used by a mobilestation device in which no C-RNTI is set or recognized. A controlchannel with CRC scrambled using the M-RNTI is used for scheduling theMBMS. A control channel with a CRC scrambled using the eIMTA-RNTI isused for notifying of information related to a TDD UL/DL setting of aTDD serving cell in dynamic TDD (eIMTA). Further, the DCI format may bescrambled using a new RNTI instead of the above RNTI.

The scheduling information (downlink scheduling information, uplinkscheduling information, and sidelink scheduling information) includesinformation for scheduling in units of resource blocks or in units ofresource block groups as scheduling in the frequency domain. Theresource block group is a set of consecutive resource blocks andindicates resources allocated to the terminal device to be scheduled.The size of the resource block group is decided in accordance with asystem bandwidth.

Details of Downlink Control Channel in Present Embodiment

The DCI is transmitted using the PDCCH or the EPDCCH. The terminaldevice 2 monitors a set of PDCCH candidates and/or a set of EPDCCHcandidates of one or more activated serving cells set by RRC signaling.Here, the monitoring means that the PDCCH and/or the EPDCCH in the setcorresponding to all the DCI formats to be monitored is attempted to bedecoded.

A set of PDCCH candidates or a set of EPDCCH candidates is also referredto as a search space. In the search space, a shared search space (CSS)and a terminal specific search space (USS) are defined. The CSS may bedefined only for the search space for the PDCCH.

A common search space (CSS) is a search space set on the basis of aparameter specific to the base station device 1 and/or a parameter whichis specified in advance. For example, the CSS is a search space used incommon to a plurality of terminal devices. Therefore, the base stationdevice 1 maps a control channel common to a plurality of terminaldevices to the CSS, and thus resources for transmitting the controlchannel are reduced.

A UE-specific search space (USS) is a search space set using at least aparameter specific to the terminal device 2. Therefore, the USS is asearch space specific to the terminal device 2, and it is possible toindividually transmit the control channel specific to the terminaldevice 2. For this reason, the base station device 1 can efficiently mapthe control channels specific to a plurality of terminal devices.

The USS may be set to be used in common to a plurality of terminaldevices. Since a common USS is set in a plurality of terminal devices, aparameter specific to the terminal device 2 is set to be the same valueamong a plurality of terminal devices. For example, a unit set to thesame parameter among a plurality of terminal devices is a cell, atransmission point, a group of predetermined terminal devices, or thelike.

The search space of each aggregation level is defined by a set of PDCCHcandidates. Each PDCCH is transmitted using one or more CCE sets. Thenumber of CCEs used in one PDCCH is also referred to as an aggregationlevel. For example, the number of CCEs used in one PDCCH is 1, 2, 4, or8.

The search space of each aggregation level is defined by a set of EPDCCHcandidates. Each EPDCCH is transmitted using one or more enhancedcontrol channel element (ECCE) sets. The number of ECCEs used in oneEPDCCH is also referred to as an aggregation level. For example, thenumber of ECCEs used in one EPDCCH is 1, 2, 4, 8, 16, or 32.

The number of PDCCH candidates or the number of EPDCCH candidates isdecided on the basis of at least the search space and the aggregationlevel. For example, in the CSS, the number of PDCCH candidates in theaggregation levels 4 and 8 are 4 and 2, respectively. For example, inthe USS, the number of PDCCH candidates in the aggregation 1, 2, 4, and8 are 6, 6, 2, and 2, respectively.

Each ECCE includes a plurality of EREGs. The EREG is used to definemapping to the resource element of the EPDCCH. 16 EREGs which areassigned numbers of 0 to 15 are defined in each RB pair. In other words,an EREG 0 to an EREG 15 are defined in each RB pair. For each RB pair,the EREG 0 to the EREG 15 are preferentially defined at regularintervals in the frequency direction for resource elements other thanresource elements to which a predetermined signal and/or channel ismapped. For example, the EREG is not defined for a resource element towhich a demodulation reference signal associated with an EPDCCHtransmitted through antenna ports 107 to 110 is mapped.

The number of ECCEs used in one EPDCCH depends on an EPDCCH format andis decided on the basis of other parameters. The number of ECCEs used inone EPDCCH is also referred to as an aggregation level. For example, thenumber of ECCEs used in one EPDCCH is decided on the basis of the numberof resource elements which can be used for transmission of the EPDCCH inone RB pair, a transmission method of the EPDCCH, and the like. Forexample, the number of ECCEs used in one EPDCCH is 1, 2, 4, 8, 16, or32. Further, the number of EREGs used in one ECCE is decided on thebasis of a type of sub frame and a type of cyclic prefix and is 4 or 8.Distributed transmission and localized transmission are supported as thetransmission method of the EPDCCH.

The distributed transmission or the localized transmission can be usedfor the EPDCCH. The distributed transmission and the localizedtransmission differ in mapping of the ECCE to the EREG and the RB pair.For example, in the distributed transmission, one ECCE is configuredusing EREGs of a plurality of RB pairs. In the localized transmission,one ECCE is configured using an EREG of one RB pair.

The base station device 1 performs a setting related to the EPDCCH inthe terminal device 2. The terminal device 2 monitors a plurality ofEPDCCHs on the basis of the setting from the base station device 1. Aset of RB pairs that the terminal device 2 monitors the EPDCCH can beset. The set of RB pairs is also referred to as an EPDCCH set or anEPDCCH-PRB set. One or more EPDCCH sets can be set in one terminaldevice 2. Each EPDCCH set includes one or more RB pairs. Further, thesetting related to the EPDCCH can be individually performed for eachEPDCCH set.

The base station device 1 can set a predetermined number of EPDCCH setsin the terminal device 2. For example, up to two EPDCCH sets can be setas an EPDCCH set 0 and/or an EPDCCH set 1. Each of the EPDCCH sets canbe constituted by a predetermined number of RB pairs. Each EPDCCH setconstitutes one set of ECCEs. The number of ECCEs configured in oneEPDCCH set is decided on the basis of the number of RB pairs set as theEPDCCH set and the number of EREGs used in one ECCE. In a case in whichthe number of ECCEs configured in one EPDCCH set is N, each EPDCCH setconstitutes ECCEs 0 to N−1. For example, in a case in which the numberof EREGs used in one ECCE is 4, the EPDCCH set constituted by 4 RB pairsconstitutes 16 ECCEs.

Details of Channel State Information in Present Embodiment

The terminal device 2 reports the CSI to the base station device 1. Thetime and frequency resources used to report the CSI are controlled bythe base station device 1. In the terminal device 2, a setting relatedto the CSI is performed through the RRC signaling from the base stationdevice 1. In the terminal device 2, one or more CSI processes are set ina predetermined transmission mode. The CSI reported by the terminaldevice 2 corresponds to the CSI process. For example, the CSI process isa unit of control or setting related to the CSI. For each of the CSIprocesses, a setting related to the CSI-RS resources, the CSI-IMresources, the periodic CSI report (for example, a period and an offsetof a report), and/or the non-periodic CSI report can be independentlyset.

The CSI includes a channel quality indicator (CQI), a precoding matrixindicator (PMI), a precoding type indicator (PTI), a rank indicator(RI), and/or a CSI-RS resource indicator (CRI). The RI indicates thenumber of transmission layers (the number of ranks). The PMI isinformation indicating a precoding matrix which is specified in advance.The PMI indicates one precoding matrix by one piece of information ortwo pieces of information. In a case in which two pieces of informationare used, the PMI is also referred to as a first PMI and a second PMI.The CQI is information indicating a combination of a modulation schemeand a coding rate which are specified in advance. The CRI is information(single instance) indicating one CSI-RS resource selected from two ormore CSI-RS resources in a case in which the two or more CSI-RSresources are set in one CSI process. The terminal device 2 reports theCSI to recommend to the base station device 1. The terminal device 2reports the CQI satisfying a predetermined reception quality for eachtransport block (codeword).

In the CRI report, one CSI-RS resource is selected from the CSI-RSresources to be set. In a case in which the CRI is reported, the PMI,the CQI, and the RI to be reported are calculated (selected) on thebasis of the reported CRI. For example, in a case in which the CSI-RSresources to be set are precoded, the terminal device 2 reports the CRI,so that precoding (beam) suitable for the terminal device 2 is reported.

A sub frame (reporting instances) in which periodic CSI reporting can beperformed are decided by a report period and a sub frame offset set by aparameter of a higher layer (a CQIPMI index, an RI index, and a CRIindex). Further, the parameter of the higher layer can be independentlyset in a sub frame set to measure the CSI. In a case in which only onepiece of information is set in a plurality of sub frame sets, thatinformation can be set in common to the sub frame sets. In each servingcell, one or more periodic CSI reports are set by the signaling of thehigher layer.

A CSI report type supports a PUCCH CSI report mode. The CSI report typeis also referred to as a PUCCH report type. A type 1 report supportsfeedback of the CQI for a terminal selection sub band. A type 1a reportsupports feedbank of a sub band CQI and a second PMI. Type 2, type 2b,type 2c reports support feedback of a wideband CQI and a PMI. A type 2areport supports feedback of a wideband PMI. A type 3 report supportsfeedback of the RI. A type 4 report supports feedback of the widebandCQI. A type 5 report supports feedback of the RI and the wideband PMI. Atype 6 report supports feedback of the RI and the PTI. A type 7 reportsupports feedback of the CRI and the RI. A type 8 report supportsfeedback of the CRI, the RI, and the wideband PMI. A type 9 reportsupports feedback of the CRI, the RI, and the PTI. A type 10 reportsupports feedback of the CRI.

In the terminal device 2, information related to the CSI measurement andthe CSI report is set from the base station device 1. The CSImeasurement is performed on the basis of the reference signal and/or thereference resources (for example, the CRS, the CSI-RS, the CSI-IMresources, and/or the DRS). The reference signal used for the CSImeasurement is decided on the basis of the setting of the transmissionmode or the like. The CSI measurement is performed on the basis ofchannel measurement and interference measurement. For example, power ofa desired cell is measured through the channel measurement. Power andnoise power of a cell other than a desired cell are measured through theinterference measurement.

For example, in the CSI measurement, the terminal device 2 performs thechannel measurement and the interference measurement on the basis of theCRS. For example, in the CSI measurement, the terminal device 2 performsthe channel measurement on the basis of the CSI-RS and performs theinterference measurement on the basis of the CRS. For example, in theCSI measurement, the terminal device 2 performs the channel measurementon the basis of the CSI-RS and performs the interference measurement onthe basis of the CSI-IM resources.

The CSI process is set as information specific to the terminal device 2through signaling of the higher layer. In the terminal device 2, one ormore CSI processes are set, and the CSI measurement and the CSI reportare performed on the basis of the setting of the CSI process. Forexample, in a case in which a plurality of CSI processes are set, theterminal device 2 independently reports a plurality of CSIs based on theCSI processes. Each CSI process includes a setting for the cell stateinformation, an identifier of the CSI process, setting informationrelated to the CSI-RS, setting information related to the CSI-IM, a subframe pattern set for the CSI report, setting information related to theperiodic CSI report, setting information related to the non-periodic CSIreport. Further, the setting for the cell state information may becommon to a plurality of CSI processes.

The terminal device 2 uses the CSI reference resources to perform theCSI measurement. For example, the terminal device 2 measures the CSI ina case in which the PDSCH is transmitted using a group of downlinkphysical resource blocks indicated by the CSI reference resources. In acase in which the CSI sub frame set is set through the signaling of thehigher layer, each CSI reference resource belongs to one of the CSI subframe sets and does not belong to both of the CSI sub frame sets.

In the frequency direction, the CSI reference resource is defined by thegroup of downlink physical resource blocks corresponding to the bandsassociated with the value of the measured CQI.

In the layer direction (spatial direction), the CSI reference resourcesare defined by the RI and the PMI whose conditions are set by themeasured CQI. In other words, in the layer direction (spatialdirection), the CSI reference resources are defined by the RI and thePMI which are assumed or generated when the CQI is measured.

In the time direction, the CSI reference resources are defined by one ormore predetermined downlink sub frames. Specifically, the CSI referenceresources are defined by a valid sub frame which is a predeterminednumber before a sub frame for reporting the CSI. The predeterminednumber of sub frames for defining the CSI reference resources is decidedon the basis of the transmission mode, the frame configuration type, thenumber of CSI processes to be set, and/or the CSI report mode. Forexample, in a case in which one CSI process and the periodic CSI reportmode are set in the terminal device 2, the predetermined number of subframes for defining the CSI reference resource is a minimum value of 4or more among valid downlink sub frames.

A valid sub frame is a sub frame satisfying a predetermined condition. Adownlink sub frame in a serving cell is considered to be valid in a casein which some or all of the following conditions are satisfied:

(1) A valid downlink sub frame is a sub frame in an ON state in theterminal device 2 in which the RRC parameters related to the ON stateand the OFF state are set;

(2) A valid downlink sub frame is set as the downlink sub frame in theterminal device 2;

(3) A valid downlink sub frame is not a multimedia broadcast multicastservice single frequency network (MBSFN) sub frame in a predeterminedtransmission mode;

(4) A valid downlink sub frame is not included in a range of ameasurement interval (measurement gap) set in the terminal device 2;

(5) A valid downlink sub frame is an element or part of a CSI sub frameset linked to a periodic CSI report when the CSI sub frame set is set inthe terminal device 2 in the periodic CSI report; and

(6) A valid downlink sub frame is an element or part of a CSI sub frameset linked to a downlink sub frame associated with a corresponding CSIrequest in an uplink DCI format in a non-periodic CSI report for the CSIprocess. Under these conditions, a predetermined transmission mode, aplurality of CSI processes, and a CSI sub frame set for the CSI processare set in the terminal device 2.

Details of Multicarrier Transmission in Present Embodiment

A plurality of cells are set for the terminal device 2, and the terminaldevice 2 can perform multicarrier transmission. Communication in whichthe terminal device 2 uses a plurality of cells is referred to ascarrier aggregation (CA) or dual connectivity (DC). Contents describedin the present embodiment can be applied to each or some of a pluralityof cells set in the terminal device 2. The cell set in the terminaldevice 2 is also referred to as a serving cell.

In the CA, a plurality of serving cells to be set includes one primarycell (PCell) and one or more secondary cells (SCell). One primary celland one or more secondary cells can be set in the terminal device 2 thatsupports the CA.

The primary cell is a serving cell in which the initial connectionestablishment procedure is performed, a serving cell that the initialconnection re-establishment procedure is started, or a cell indicated asthe primary cell in a handover procedure. The primary cell operates witha primary frequency. The secondary cell can be set after a connection isconstructed or reconstructed. The secondary cell operates with asecondary frequency. Further, the connection is also referred to as anRRC connection.

The DC is an operation in which a predetermined terminal device 2consumes radio resources provided from at least two different networkpoints. The network point is a master base station device (a master eNB(MeNB)) and a secondary base station device (a secondary eNB (SeNB)). Inthe dual connectivity, the terminal device 2 establishes an RRCconnection through at least two network points. In the dualconnectivity, the two network points may be connected through anon-ideal backhaul.

In the DC, the base station device 1 which is connected to at least anS1-MME and plays a role of a mobility anchor of a core network isreferred to as a master base station device. Further, the base stationdevice 1 which is not the master base station device providingadditional radio resources to the terminal device 2 is referred to as asecondary base station device. A group of serving cells associated withthe master base station device is also referred to as a master cellgroup (MCG). A group of serving cells associated with the secondary basestation device is also referred to as a secondary cell group (SCG).

In the DC, the primary cell belongs to the MCG Further, in the SCG thesecondary cell corresponding to the primary cell is referred to as aprimary secondary cell (PSCell). A function (capability and performance)equivalent to the PCell (the base station device constituting the PCell)may be supported by the PSCell (the base station device constituting thePSCell). Further, the PSCell may only support some functions of thePCell. For example, the PSCell may support a function of performing thePDCCH transmission using the search space different from the CSS or theUSS. Further, the PSCell may constantly be in an activation state.Further, the PSCell is a cell that can receive the PUCCH.

In the DC, a radio bearer (a date radio bearer (DRB)) and/or a signalingradio bearer (SRB) may be individually allocated through the MeNB andthe SeNB. A duplex mode may be set individually in each of the MCG(PCell) and the SCG (PSCell). The MCG (PCell) and the SCG (PSCell) maynot be synchronized with each other. A parameter (a timing advance group(TAG)) for adjusting a plurality of timings may be independently set inthe MCG (PCell) and the SCG (PSCell). In the dual connectivity, theterminal device 2 transmits the UCI corresponding to the cell in the MCGonly through MeNB (PCell) and transmits the UCI corresponding to thecell in the SCG only through SeNB (pSCell). In the transmission of eachUCI, the transmission method using the PUCCH and/or the PUSCH is appliedin each cell group.

The PUCCH and the PBCH (MIB) are transmitted only through the PCell orthe PSCell. Further, the PRACH is transmitted only through the PCell orthe PSCell as long as a plurality of TAGs are not set between cells inthe CG.

In the PCell or the PSCell, semi-persistent scheduling (SPS) ordiscontinuous transmission (DRX) may be performed. In the secondarycell, the same DRX as the PCell or the PSCell in the same cell group maybe performed.

In the secondary cell, information/parameter related to a setting of MACis basically shared with the PCell or the PSCell in the same cell group.Some parameters may be set for each secondary cell. Some timers orcounters may be applied only to the PCell or the PSCell.

In the CA, a cell to which the TDD scheme is applied and a cell to whichthe FDD scheme is applied may be aggregated. In a case in which the cellto which the TDD is applied and the cell to which the FDD is applied areaggregated, the present disclosure can be applied to either the cell towhich the TDD is applied or the cell to which the FDD is applied.

The terminal device 2 transmits information indicating a combination ofbands in which the CA is supported by the terminal device 2 to the basestation device 1. The terminal device 2 transmits information indicatingwhether or not simultaneous transmission and reception are supported ina plurality of serving cells in a plurality of different bands for eachof band combinations to the base station device 1.

Details of Resource Allocation in Present Embodiment

The base station device 1 can use a plurality of methods as a method ofallocating resources of the PDSCH and/or the PUSCH to the terminaldevice 2. The resource allocation method includes dynamic scheduling,semi persistent scheduling, multi sub frame scheduling, and cross subframe scheduling.

In the dynamic scheduling, one DCI performs resource allocation in onesub frame. Specifically, the PDCCH or the EPDCCH in a certain sub frameperforms scheduling for the PDSCH in the sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in apredetermined sub frame after the certain sub frame.

In the multi sub frame scheduling, one DCI allocates resources in one ormore sub frames. Specifically, the PDCCH or the EPDCCH in a certain subframe performs scheduling for the PDSCH in one or more sub frames whichare a predetermined number after the certain sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in oneor more sub frames which are a predetermined number after the sub frame.The predetermined number can be set to an integer of zero or more. Thepredetermined number may be specified in advance and may be decided onthe basis of the signaling of the physical layer and/or the RRCsignaling. In the multi sub frame scheduling, consecutive sub frames maybe scheduled, or sub frames with a predetermined period may bescheduled. The number of sub frames to be scheduled may be specified inadvance or may be decided on the basis of the signaling of the physicallayer and/or the RRC signaling.

In the cross sub frame scheduling, one DCI allocates resources in onesub frame. Specifically, the PDCCH or the EPDCCH in a certain sub frameperforms scheduling for the PDSCH in one sub frame which is apredetermined number after the certain sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in onesub frame which is a predetermined number after the sub frame. Thepredetermined number can be set to an integer of zero or more. Thepredetermined number may be specified in advance and may be decided onthe basis of the signaling of the physical layer and/or the RRCsignaling. In the cross sub frame scheduling, consecutive sub frames maybe scheduled, or sub frames with a predetermined period may bescheduled.

In the semi-persistent scheduling (SPS), one DCI allocates resources inone or more sub frames. In a case in which information related to theSPS is set through the RRC signaling, and the PDCCH or the EPDCCH foractivating the SPS is detected, the terminal device 2 activates aprocess related to the SPS and receives a predetermined PDSCH and/orPUSCH on the basis of a setting related to the SPS. In a case in whichthe PDCCH or the EPDCCH for releasing the SPS is detected when the SPSis activated, the terminal device 2 releases (inactivates) the SPS andstops reception of a predetermined PDSCH and/or PUSCH. The release ofthe SPS may be performed on the basis of a case in which a predeterminedcondition is satisfied. For example, in a case in which a predeterminednumber of empty transmission data is received, the SPS is released. Thedata empty transmission for releasing the SPS corresponds to a MACprotocol data unit (PDU) including a zero MAC service data unit (SDU).

Information related to the SPS by the RRC signaling includes an SPSC-RNTI which is an SPN RNTI, information related to a period (interval)in which the PDSCH is scheduled, information related to a period(interval) in which the PUSCH is scheduled, information related to asetting for releasing the SPS, and/or a number of the HARQ process inthe SPS. The SPS is supported only in the primary cell and/or theprimary secondary cell.

Details of Downlink Resource Element Mapping in Present Embodiment

FIG. 5 is a diagram illustrating an example of downlink resource elementmapping in the present embodiment. In this example, a set of resourceelements in one resource block pair in a case in which one resourceblock and the number of OFDM symbols in one slot are 7 will bedescribed. Further, seven OFDM symbols in a first half in the timedirection in the resource block pair are also referred to as a slot 0 (afirst slot). Seven OFDM symbols in a second half in the time directionin the resource block pair are also referred to as a slot 1 (a secondslot). Further, the OFDM symbols in each slot (resource block) areindicated by OFDM symbol number 0 to 6. Further, the sub carriers in thefrequency direction in the resource block pair are indicated by subcarrier numbers 0 to 11. Further, in a case in which a system bandwidthis constituted by a plurality of resource blocks, a different subcarrier number is allocated over the system bandwidth. For example, in acase in which the system bandwidth is constituted by six resourceblocks, the sub carriers to which the sub carrier numbers 0 to 71 areallocated are used. Further, in the description of the presentembodiment, a resource element (k, 1) is a resource element indicated bya sub carrier number k and an OFDM symbol number 1.

Resource elements indicated by R 0 to R 3 indicate cell-specificreference signals of the antenna ports 0 to 3, respectively.Hereinafter, the cell-specific reference signals of the antenna ports 0to 3 are also referred to as cell-specific RSs (CRSs). In this example,the case of the antenna ports in which the number of CRSs is 4 isdescribed, but the number thereof can be changed. For example, the CRScan use one antenna port or two antenna ports. Further, the CRS canshift in the frequency direction on the basis of the cell ID. Forexample, the CRS can shift in the frequency direction on the basis of aremainder obtained by dividing the cell ID by 6.

Resource element indicated by C1 to C4 indicates reference signals(CSI-RS) for measuring transmission path states of the antenna ports 15to 22. The resource elements denoted by C1 to C4 indicate CSI-RSs of acode division multiplexing (CDM) group 1 to a CDM group 4, respectively.The CSI-RS is constituted by an orthogonal sequence (orthogonal code)using a Walsh code and a scramble code using a pseudo random sequence.Further, the CSI-RS is code division multiplexed using an orthogonalcode such as a Walsh code in the CDM group. Further, the CSI-RS isfrequency-division multiplexed (FDM) mutually between the CDM groups.

The CSI-RSs of the antenna ports 15 and 16 are mapped to C1. The CSI-RSsof the antenna ports 17 and 18 is mapped to C2. The CSI-RSs of theantenna port 19 and 20 are mapped to C3. The CSI-RSs of the antenna port21 and 22 are mapped to C4.

A plurality of antenna ports of the CSI-RSs are specified. The CSI-RScan be set as a reference signal corresponding to eight antenna ports ofthe antenna ports 15 to 22. Further, the CSI-RS can be set as areference signal corresponding to four antenna ports of the antennaports 15 to 18. Further, the CSI-RS can be set as a reference signalcorresponding to two antenna ports of the antenna ports 15 to 16.Further, the CSI-RS can be set as a reference signal corresponding toone antenna port of the antenna port 15. The CSI-RS can be mapped tosome sub frames, and, for example, the CSI-RS can be mapped for everytwo or more sub frames. A plurality of mapping patterns are specifiedfor the resource element of the CSI-RS. Further, the base station device1 can set a plurality of CSI-RSs in the terminal device 2.

The CSI-RS can set transmission power to zero. The CSI-RS with zerotransmission power is also referred to as a zero power CSI-RS. The zeropower CSI-RS is set independently of the CSI-RS of the antenna ports 15to 22. Further, the CSI-RS of the antenna ports 15 to 22 is alsoreferred to as a non-zero power CSI-RS.

The base station device 1 sets CSI-RS as control information specific tothe terminal device 2 through the RRC signaling. In the terminal device2, the CSI-RS is set through the RRC signaling by the base stationdevice 1. Further, in the terminal device 2, the CSI-IM resources whichare resources for measuring interference power can be set. The terminaldevice 2 generates feedback information using the CRS, the CSI-RS,and/or the CSI-IM resources on the basis of a setting from the basestation device 1.

Resource elements indicated by D1 to D2 indicate the DL-DMRSs of the CDMgroup 1 and the CDM group 2, respectively. The DL-DMRS is constitutedusing an orthogonal sequence (orthogonal code) using a Walsh code and ascramble sequence according to a pseudo random sequence. Further, theDL-DMRS is independent for each antenna port and can be multiplexedwithin each resource block pair. The DL-DMRSs are in an orthogonalrelation with each other between the antenna ports in accordance withthe CDM and/or the FDM. Each of DL-DMRSs undergoes the CDM in the CDMgroup in accordance with the orthogonal codes. The DL-DMRSs undergo theFDM with each other between the CDM groups. The DL-DMRSs in the same CDMgroup are mapped to the same resource element. For the DL-DMRSs in thesame CDM group, different orthogonal sequences are used between theantenna ports, and the orthogonal sequences are in the orthogonalrelation with each other. The DL-DMRS for the PDSCH can use some or allof the eight antenna ports (the antenna ports 7 to 14). In other words,the PDSCH associated with the DL-DMRS can perform MIMO transmission ofup to 8 ranks. The DL-DMRS for the EPDCCH can use some or all of thefour antenna ports (the antenna ports 107 to 110). Further, the DL-DMRScan change a spreading code length of the CDM or the number of resourceelements to be mapped in accordance with the number of ranks of anassociated channel.

The DL-DMRS for the PDSCH to be transmitted through the antenna ports 7,8, 11, and 13 are mapped to the resource element indicated by D1. TheDL-DMRS for the PDSCH to be transmitted through the antenna ports 9, 10,12, and 14 are mapped to the resource element indicated by D2. Further,the DL-DMRS for the EPDCCH to be transmitted through the antenna ports107 and 108 are mapped to the resource element indicated by D1. TheDL-DMRS for the EPDCCH to be transmitted through the antenna ports 109and 110 are mapped to the resource element denoted by D2.

HARQ in Present Embodiment

In the present embodiment, the HARQ has various features. The HARQtransmits and retransmits the transport block. In the HARQ, apredetermined number of processes (HARQ processes) are used (set), andeach process independently operates in accordance with a stop-and-waitscheme.

In the downlink, the HARQ is asynchronous and operates adaptively. Inother words, in the downlink, retransmission is constantly scheduledthrough the PDCCH. The uplink HARQ-ACK (response information)corresponding to the downlink transmission is transmitted through thePUCCH or the PUSCH. In the downlink, the PDCCH notifies of a HARQprocess number indicating the HARQ process and information indicatingwhether or not transmission is initial transmission or retransmission.

In the uplink, the HARQ operates in a synchronous or asynchronousmanner. The downlink HARQ-ACK (response information) corresponding tothe uplink transmission is transmitted through the PHICH. In the uplinkHARQ, an operation of the terminal device is decided on the basis of theHARQ feedback received by the terminal device and/or the PDCCH receivedby the terminal device. For example, in a case in which the PDCCH is notreceived, and the HARQ feedback is ACK, the terminal device does notperform transmission (retransmission) but holds data in a HARQ buffer.In this case, the PDCCH may be transmitted in order to resume theretransmission. Further, for example, in a case in which the PDCCH isnot received, and the HARQ feedback is NACK, the terminal deviceperforms retransmission non-adaptively through a predetermined uplinksub frame. Further, for example, in a case in which the PDCCH isreceived, the terminal device performs transmission or retransmission onthe basis of contents notified through the PDCCH regardless of contentof the HARQ feedback.

Further, in the uplink, in a case in which a predetermined condition(setting) is satisfied, the HARQ may be operated only in an asynchronousmanner. In other words, the downlink HARQ-ACK is not transmitted, andthe uplink retransmission may constantly be scheduled through the PDCCH.

In the HARQ-ACK report, the HARQ-ACK indicates ACK, NACK, or DTX. In acase in which the HARQ-ACK is ACK, it indicates that the transport block(codeword and channel) corresponding to the HARQ-ACK is correctlyreceived (decoded). In a case in which the HARQ-ACK is NACK, itindicates that the transport block (codeword and channel) correspondingto the HARQ-ACK is not correctly received (decoded). In a case in whichthe HARQ-ACK is DTX, it indicates that the transport block (codeword andchannel) corresponding to the HARQ-ACK is not present (not transmitted).

A predetermined number of HARQ processes are set (specified) in each ofdownlink and uplink. For example, in FDD, up to eight HARQ processes areused for each serving cell. Further, for example, in TDD, a maximumnumber of HARQ processes is decided by an uplink/downlink setting. Amaximum number of HARQ processes may be decided on the basis of a roundtrip time (RTT). For example, in a case in which the RTT is 8 TTIs, themaximum number of the HARQ processes can be 8.

In the present embodiment, the HARQ information is constituted by atleast a new data indicator (NDI) and a transport block size (TBS). TheNDI is information indicating whether or not the transport blockcorresponding to the HARQ information is initial transmission orretransmission. The TBS is the size of the transport block. Thetransport block is a block of data in a transport channel (transportlayer) and can be a unit for performing the HARQ. In the DL-SCHtransmission, the HARQ information further includes a HARQ process ID (aHARQ process number). In the UL-SCH transmission, the HARQ informationfurther includes an information bit in which the transport block isencoded and a redundancy version (RV) which is information specifying aparity bit. In the case of spatial multiplexing in the DL-SCH, the HARQinformation thereof includes a set of NDI and TBS for each transportblock.

TTI in Present Embodiment

FIG. 6 is a diagram illustrating an example of the TTI in the presentembodiment. In the example of FIG. 6, the TTI is a 1 sub frame. In otherwords, a unit of data transmission in the time domain such as the PDSCH,the PUSCH, or the HARQ-ACK is a 1 sub frame. Arrows between downlink anduplink indicate a HARQ timing and/or a scheduling timing. The HARQtiming and the scheduling timing are specified or set in units of subframes which are TTIs. For example, in a case in which a certain PDSCHis transmitted through a downlink sub frame n, the HARQ-ACK for thePDSCH is transmitted through an uplink sub frame n+4 after 4 sub frames.For example, in a case in which the PDCCH for notifying of the uplinkgrant is transmitted through a downlink sub frame n, the PUSCHcorresponding to the uplink grant is transmitted through an uplink subframe n+4 after 4 sub frames, and the HARQ-ACK for the PUSCH is notifiedthrough a downlink sub frame n+8 after 4 sub frames. Further, in FIG. 6,an example in which the TTI is a 1 sub frame is described, but the TTImay be a plurality of sub frames. In other words, the TTI may be aninteger multiple of a sub frame length.

FIG. 7 is a diagram illustrating an example of the TTI in the presentembodiment. In the example of FIG. 7, the TTI is a 1 symbol. In otherwords, a unit of data transmission in the time domain such as the PDSCH,the PUSCH, or the HARQ-ACK is a 1 symbol. Arrows between downlink anduplink indicate a HARQ timing and/or a scheduling timing. The HARQtiming and the scheduling timing are specified or set in units ofsymbols which are TTIs. For example, in a case in which a certain PDSCHis transmitted through a downlink symbol n, the HARQ-ACK for the PDSCHis transmitted through an uplink symbol n+4 after 4 symbols. Forexample, in a case in which the PDCCH for notifying of the uplink grantis transmitted through a downlink symbol n, the PUSCH corresponding tothe uplink grant is transmitted through an uplink symbol n+4 after 4symbols, and the HARQ-ACK for the PUSCH is notified through a downlinksymbol n+8 after 4 symbols. Further, in FIG. 6, an example in which theTTI is a 1 symbol is described, but the TTI may be a plurality ofsymbols. In other words, the TTI may be an integer multiple of a symbollength.

A difference between FIG. 6 and FIG. 7 lies in that the TTIs havedifferent sizes (lengths). Further, as described above, in a case inwhich the HARQ timing and the scheduling timing are specified or set onthe basis of the TTI, the HARQ timing and the scheduling timing can beadjusted to earlier timings by reducing the TTI. Since the HARQ timingand the scheduling timing are factors for deciding the latency of thesystem, reducing the TTI reduces the latency. For example, the reductionin the latency is important for data (packet) intended for safetypurpose such as intelligent transportation system. On the other hand, ina case in which the TTI is reduced, the maximum value of the TBStransmitted at one TTI is reduced, and an overhead of controlinformation is likely to increase. Therefore, it is preferable that theTTI be specified or set in accordance with the purpose or the use ofdata. For example, the base station device can specify or set the size(length) and/or the mode of the TTI in a cell-specific manner or aterminal device specific manner. Further, in a case in which the HARQtiming and the scheduling timing are specified or set on the basis ofthe TTI the maximum value of the TBS transmitted in the latency and/orone TTI can be adaptively set by changing the size (length) of the TTI.Accordingly, efficient data transmission in which the latency isconsidered can be performed. Further, in the description of the presentembodiment, the sub frame, the symbol, the OFDM symbol, and the SC-FDMAsymbol can be interpreted as the TTI.

Setting Related to TTI in Present Embodiment

In the present embodiment, sizes of a plurality of TTIs are specified.For example, a plurality of modes (TTI modes) related to the size of theTTI are specified, and the base station device sets the mode in theterminal device through the signaling of the higher layer. The basestation device performs data transmission on the basis of the TTI modeset in the terminal device. The terminal device performs datatransmission on the basis of the TTI mode set by the base stationdevice. The setting of the TTI mode can be performed individually foreach cell (serving cell).

A first TTI mode is a mode in which the TTI is based on the sub frame,and a second TTI mode is a mode in which the TTI is based on the symbol.For example, the TTI illustrated in FIG. 6 is used in the first TTImode, and the TTI illustrated in FIG. 7 is used in the second TTI mode.Further, for example, in the first TTI mode, the TTI is an integermultiple of the sub frame length, and in the second TTI mode, the TTI isan integer multiple of the symbol length. Further, for example, in thefirst TTI mode, the TTI is specified through a 1 sub frame used in asystem of a related art, and in the second TTI mode, the TTI isspecified as an integer multiple of the symbol length which is not usedin the system of the related art. Further, the TTI specified or set inthe first TTI mode is also referred to as a first TTI, and the TTIspecified or set in the second TTI mode is also referred to as a secondTTI.

Various methods can be used for setting the TTI mode. In one example ofthe setting of the TTI mode, the first TTI mode or the second TTI modeis set in the terminal device through the signaling of the higher layer.In a case in which the first TTI mode is set, data transmission isperformed on the basis of the first TTI. In a case in which the secondTTI mode is set, data transmission is performed on the basis of thesecond TTI. In another example of the setting of the TTI mode, thesecond TTI mode (an extended TTI mode or a short TTI (STTI) mode) is setin the terminal device through the signaling of the higher layer. In acase in which the second TTI mode is not set, data transmission isperformed on the basis of the first TTI. In a case in which the secondTTI mode is set, data transmission is performed on the basis of thesecond TTI. Further, the second TTI is also referred to as an extendedTTI or an STTI.

The setting related to the STTI (STTI setting) is performed through theRRC signaling and/or the signaling of the physical layer. The STTIsetting includes information (parameter) related to the TTI size, asetting related to the STTI in the downlink (downlink STTI setting), asetting related to the STTI in the uplink (uplink STTI setting), and/orinformation for monitoring the control channel for notifying of thecontrol information related to the STTI. The STTI setting can beindividually set for each cell (serving cell).

The setting related to the STTI in the downlink is a setting fortransmission (transmission and reception) of the downlink channel (thePDSCH, the PDCCH, and/or the EPDCCH) in the STTI mode, and includes asetting related to the downlink channel in the STTI mode. For example,the setting related to the STTI in the downlink includes a settingrelated to the PDSCH in the STTI mode, a setting related to the PDCCH inthe STTI mode, and/or a setting related to the EPDCCH in the STTI mode.

The setting related to the STTI in the uplink is a setting fortransmission (transmission and reception) of the uplink channel (thePUSCH and/or the PUCCH) in the STTI mode, and includes a setting relatedto the uplink channel in the STTI mode. For example, the setting relatedto the STTI in the uplink includes a setting related to the PUSCH in theSTTI mode, and/or a setting related to the PUCCH in the STTI mode.

The information for monitoring the control channel for notifying of thecontrol information related to the STTI is an RNTI used for scramblingthe CRC added to the control information (DCI) related to the STTI. TheRNTI is also referred to as an STTI-RNTI. Further, the STTI-RNTI may beset in common to the STTI in the downlink and the STTI in the uplink ormay be set independently. Further, in a case in which a plurality ofSTTI settings are set, the STTI-RNTI may be set in common to all theSTTI settings or may be independently set.

The information related to the TTI size is information indicating thesize of the TTI in the STTI mode (that is, the size of the STTI). Forexample, the information related to the TTI size includes the number ofOFDM symbols for setting the TTI in units of OFDM symbols. Further, in acase in which the information related to the TTI size is not included inthe STTI setting, the TTI size can be se to a value which is specifiedin advance. For example, in a case in which the information related tothe TTI size is not included in the STTI setting, the TTI size is a 1symbol length or a 1 sub frame length. Further, the information relatedto the TTI size may be set in common to the STTI in the downlink and theSTTI in the uplink or may be set independently. Further, in a case inwhich a plurality of STTI settings are set, the information related tothe TTI size may be set in common to all the STTI settings or may be setindependently.

In the description of the present embodiment, a channel (STTI channel)in the STTI mode includes a downlink channel in the STTI mode and/or anuplink channel in the STTI mode. A setting related to the channel in theSTTI mode (STTI channel setting) includes a setting related to thedownlink channel in the STTI mode and/or a setting related to the uplinkchannel in the STTI mode. The PDSCH in the STTI mode is also referred toas a short PDSCH (SPDSCH), an enhanced PDSCH (EPDSCH), or a reducedPDSCH (RPDSCH). The PUSCH in the STTI mode is also referred to as ashort PUSCH (SPUSCH), an enhanced PUSCH (EPUSCH), or a reduced PUSCH(RPUSCH). The PUCCH in the STTI mode is also referred to as a shortPUCCH (SPUCCH), an enhanced PUCCH (EPUCCH), or a reduced PUCCH (RPUCCH).The STTI channel includes the SPDSCH, the SPUSCH, or the SPUCCH. TheSTTI channel setting includes an SPDSCH setting, an SPUSCH setting, oran SPUCCH setting.

In the present embodiment, data transmission and scheduling methods forthe channels in the STTI mode can use various methods or schemes. Forexample, the channel in the STTI mode is mapped to some or all of one ormore periodic resources that are set or notified through the signalingof the higher layer and/or the signaling of the physical layer.

In the present embodiment, the physical downlink shared channel in thefirst TTI mode is also referred to as a PDSCH or a first PDSCH, and thephysical downlink shared channel in the second TTI mode is also referredto as an SPDSCH or a second PDSCH.

The channel in the STTI mode is mapped on the basis of the sub resourceblock. The sub resource block is used to indicate mapping of apredetermined channel in the STTI mode to the resource element. One subresource block is defined by successive sub carriers corresponding toone TTI in the time domain and consecutive sub carriers corresponding toone resource block in the frequency domain. A certain sub resource blockmay be configured to be included in only one resource block or may beconfigured over two resource blocks. Further, a certain sub resourceblock may be configured over two resource blocks in one resource blockpair or may not be configured over a plurality of resource block pairs.

Each of the transport blocks (codeword) of the channel in the STTI modeis transmitted using one or more sub resource blocks in the same TTI.

Resources (sub resource block) to which the channel (the STTI channel)in the STTI mode can be mapped through signaling of the higher layerand/or signaling of the physical layer are set in the terminal device.The resources to which the channel in the STTI mode can be mapped isalso referred to as an STTI channel candidate. Further, a series of STTIchannel candidates set by one STTI channel setting is also referred toas a set of STTI channel candidates.

A set of the STTI channel candidates is designated by a TTI of apredetermined period in the time domain and a predetermined sub resourceblock in the frequency domain. In the same the STTI channel, a pluralityof STTI channel settings can be performed. In other words, in each setof the STTI channel candidates, the period in the time domain and/or theresources in the frequency domain can be set independently. In a case inwhich a plurality of STTI channel settings are performed, the terminaldevice can monitor the set of a plurality of STTI channel candidateswhich is set.

The STTI channel setting includes STTI channel setting information inthe time domain, STTI channel setting information in the frequencydomain, and/or information related to the HARQ-ACK for the STTI channel.Further, the STTI channel setting may further include information formonitoring the control channel for notifying of the information relatedto the TTI size and/or the control information related to the STTIchannel. The STTI channel setting information in the time domain isinformation for deciding the resources of the STTI channel candidate inthe time domain. The STTI channel setting information in the frequencydomain is information for deciding the resources of the STTI channelcandidate in the frequency domain.

The information for deciding the resources of the STTI channel candidatecan use various formats. The resources of the STTI channel in thefrequency domain are decided (set, specified, or designated) in units ofresource blocks or in units of sub resource blocks.

An example of the STTI channel setting information in the time domainincludes a predetermined number of TTI periods and a predeterminednumber of TTI offsets. The offset of the TTI is an offset (shift) from aTTI serving as a reference and is set in units of TTIs. For example, ina case in which the offset of the TTI is 3, the set of the STTI channelcandidates is set by including a TTI obtained by offsetting 3 TTIs fromthe TTI serving as the reference. For example, in a case in which theperiod of the TTI is 3, the set of the STTI channel candidate is set atintervals of every two TTIs. In a case in which the period of the TTI is1, all consecutive TTIs are set.

In another example of the STTI channel setting information in the timedomain, bitmap information indicating the TTI of the STTI channelcandidate is used. For example, one bit in the bitmap informationcorresponds to a predetermined number of sub frames or each of TTIs in apredetermined number of radio frames. In a case in which a certain bitin the bitmap information is 1, it indicates that the TTI correspondingto the bit is a TTI including the STTI channel candidate. In a case inwhich a certain bit in the bitmap information is 0, it indicates thatthe TTI corresponding to the bit is not a TTI including the STTI channelcandidate. Specifically, in a case in which the TTI size is one subframe, the number of TTIs in five sub frames is 70. In this case, thebitmap information is 70-bit information. The bitmap information isapplied from the TTI serving as the reference and repeatedly applied foreach TTI corresponding to the bitmap information.

An example of the STTI channel setting information in the frequencydomain uses bitmap information indicating sub resource blocks of theSTTI channel candidate or a set of sub resource blocks. For example, onebit in the bitmap information corresponds to each of a predeterminednumber of sets of sub resource blocks. In a case in which a certain bitin the bitmap information is 1, it indicates that the sub resource blockincluded in the set of sub resource blocks corresponding to the bit is asub resource block including the STTI channel candidate. In a case inwhich a certain bit in the bitmap information is 0, it indicates thatthe sub resource block included in the set of sub resource blockscorresponding to the bit is not a sub resource block including the STTIchannel candidate.

Another example of the STTI channel setting information in the frequencydomain uses a sub resource block serving as a start and the number ofconsecutively allocated sub resource blocks.

The set of sub resource blocks is constituted by a predetermined numberof consecutive sub resource blocks in the frequency domain. Thepredetermined number of sub resource blocks constituting the set of subresource blocks may be decided on the basis of other parameters such asthe system bandwidth or may be set through the RRC signaling. In thedescription of the present embodiment, the set of sub resource blockssimply includes the sub resource block as well.

The sub resource block set by the STTI channel setting information inthe frequency domain may be identical in all the TTIs or may be switched(hopped) at intervals of every predetermined number of TTIs. Forexample, the sub resource block of the STTI channel candidate in acertain TTI is decided further using a number (an index or information)indicating the TTI, and the sub resource block of the STTI channelcandidate is set differently for each TTI. Accordingly, the frequencydiversity effect can be expected.

The information related to the HARQ-ACK for the STTI channel includesinformation related to resources for reporting the HARQ-ACK for the STTIchannel. For example, in a case in which the STTI channel is the SPDSCH,information related to the HARQ-ACK for the STTI channel explicitly orimplicitly indicates resources in the uplink channel for reporting theHARQ-ACK for the SPDSCH.

In a case in which a plurality of STTI channel settings are set for thesame the STTI channel, all parameters in the STTI channel setting may beindependently set, or some parameters may be set in common. For example,in a plurality of STTI channel settings, the STTI channel settinginformation in the time domain and the STTI channel setting informationin the frequency domain are set independently. For example, in aplurality of STTI channel settings, the STTI channel setting informationin the time domain is set in common, and the STTI channel settinginformation in the frequency domain is set independently. For example,in a plurality of STTI channel settings, the STTI channel settinginformation in the time domain is set independently, and the STTIchannel setting information in the frequency domain is set in common.Further, only some pieces of information may be set in common, and theperiod of the TTI included in the STTI channel setting information inthe time domain may be set in common.

Some pieces of information or some parameters set by the STTI setting inthe present embodiment may be notified through signaling of the physicallayer. For example, the STTI channel setting information in thefrequency domain is notified through signaling of the physical layer.

In one example of an operation of the terminal device in the STTI mode,the terminal device operates only through signaling of the higher layer(the RRC signaling) only. In a case in which the STTI channel setting isset through signaling of the higher layer, the terminal device startsmonitoring or receiving of the corresponding STTI channel. The terminaldevice stops monitoring or receiving of the corresponding STTI channelin a case in which the STTI channel setting being set is releasedthrough signaling of the higher layer.

In another example of the operation of the terminal device in the STTImode, the terminal device operates through signaling of the higher layer(the RRC signaling) and signaling of the physical layer. In a case inwhich the STTI channel setting is set through signaling of the higherlayer, and the information (DCI) for activating scheduling of thecorresponding STTI channel is notified through signaling of the physicallayer, the terminal device starts monitoring or receiving of thecorresponding STTI channel. In a case in which the STTI channel settingis set through signaling of the higher layer. and information (DCI) forreleasing scheduling of the corresponding STTI channel is notifiedthrough signaling of the physical layer, the terminal device stopsmonitoring or receiving of the corresponding STTI channel.

In a case in which a plurality of STTI channel settings are set, theinformation for enabling the scheduling of the STTI channel or theinformation for releasing the scheduling of the STTI channel may benotified in common to the STTI channels or independently.

In a case in which a plurality of STTI channel settings are set, and theSTTI channel candidates which are set differently collide at the sameTTI (that is, in a case in which a plurality of STTI channel candidatesare set within the same TTI), the terminal device may monitor all of theSTTI channel candidate or may monitor some of the STTI channelcandidates. In a case in which some of the STTI channel candidates aremonitored, the terminal device may decide the STTI channel candidate tobe monitored on the basis of a predetermined priority. For example, thepredetermined priority is decided on the basis of a type of STTIchannel, an index (number) indicating the STTI channel setting, and/oran element (parameter) including a capability of the terminal device.

Details of SPDSCH in Present Embodiment

FIG. 8 is a diagram illustrating an example of a set of SPDSCHcandidates. In the example of FIG. 8, a first set of SPDSCH candidatesand a second set of SPDSCH candidates are set by the base station deviceof the terminal device. The TTI size is a 1 symbol. In the first set ofSPDSCH candidates, the period of the TTI is 2, and the offset of the TTIis 0. Here, the TTI serving as the reference in the offset of the TTI isa first symbol 0 in FIG. 8. In the second set of SPDSCH candidates, theperiod of the TTI is 3, and the offset of the TTI is 1. The SPDSCHcandidate is also referred to as a second PDSCH candidate.

The base station device maps the SPDSCH for the terminal device to oneof the SPDSCH candidates set in the terminal device and transmitsresulting data. The terminal device monitors the SPDSCH candidate set inthe base station device and detects the SPDSCH for the terminal device.

An example of a method of deciding whether or not the SPDSCH detected ina certain terminal device is addressed to the terminal device, andreception is performed correctly is a method of using an RNTI specificto the terminal device (for example, the STTI-RNTI). For example, eachcodeword (transport block) to which a predetermined CRC is added isscrambled using the RNTI specific to the terminal device andtransmitted. Therefore, in a case in which the terminal device receivesthe SPDSCH, since each codeword is descrambled correctly, the terminaldevice can determine that the SPDSCH is addressed to the terminal deviceon the basis of the added CRC. On the other hand, in a case in which aterminal device different from the terminal device receives the SPDSCH,since each codeword is not descrambled correctly, another the terminaldevice can determine that the SPDSCH is not addressed to itself on thebasis of the added CRC.

Another example of a method of deciding whether or not the SPDSCHdetected in a certain terminal device is addressed to the terminaldevice, and reception is performed correctly is a method of includinginformation indicating that the SPDSCH for the certain terminal deviceis addressed to the terminal device. For example, the SPDSCH for acertain terminal device contains an RNTI specific to the terminaldevice. For example, the CRC in the SPDSCH for a certain terminal deviceis scrambled using an RNTI specific to the terminal device.

The terminal device performs an operates related to the report of theHARQ-ACK for the SPDSCH or the SPDSCH candidate on the basis of whetheror not the SPDSCH addressed to the terminal device is correctly received(decode).

Here, in a case in which the SPDSCH candidate is not received (decoded)correctly in a certain terminal device, the SPDSCH candidate may be oneof the following situations:

(1) the SPDSCH is an SPDSCH addressed to the terminal device but notreceived correctly;

(2) the SPDSCH is an SPDSCH addressed to a terminal device differentfrom the terminal device; and

(3) none of SPDSCHs is transmitted to the PDSCH candidate. However, in acase in which the SPDSCH candidate is not received correctly, theterminal device may not be able to determine whether or not the SPDSCHcorresponds to one of the above situations. Therefore, in a case inwhich the SPDSCH is not correctly received by the terminal device, itmay be preferable that the same operation be performed regardless of theSPDSCH corresponds to one of the above situations.

Examples of an operation related to the HARQ-ACK report for the SPDSCHor the SPDSCH candidate in the terminal device are as follows:

(1) in a case in which the terminal device can correctly receive(decode) the SPDSCH addressed to the terminal device, the terminaldevice reports ACK as the HARQ-ACK report for the SPDSCH throughpredetermined resources. (2) in a case in which the terminal devicefails to correctly receive (decode) the SPDSCH addressed to the terminaldevice, the terminal device reports NACK and/or DTX as the HARQ-ACKreport for the SPDSCH through predetermined resources.

FIG. 9 is a diagram illustrating an example of SPDSCH transmission inthe base station device and the HARQ-ACK report in the terminal device.The base station device sets a set of SPDSCH candidates by performingthe STTI setting in the terminal device through the RRC signaling. Thebase station device notifies the terminal device of the information foractivating the scheduling of the SPDSCH through the PDCCH. The basestation device is likely to transmit the SPDSCH for the terminal deviceon the basis of the set of set SPDSCH candidates. On the other hand, theterminal device monitors the set of set SPDSCH candidates and detectsthe SPDSCH for the terminal device.

The base station device transmits the SPDSCH for the terminal device inSPDSCH candidates #1, #2, #3, and #5. Since the SPDSCHs in the SPDSCHcandidates #1, #2, and #5 are correctly decoded, the terminal devicereports the HARQ-ACK indicating ACK in the HARQ-ACK reports #1, #2, and#5. Since the SPDSCH in the SPDSCH candidate #3 is not correctlydecoded, the terminal device reports the HARQ-ACK indicating NACK and/orDTX in the HARQ-ACK report #3.

The base station device transmits the SPDSCH for another the terminaldevice in SPDSCH candidates #4 and #6. Further, the base station devicemay not transmit anything in the SPDSCH candidates #4 and #6. Since theSPDSCHs in the SPDSCH candidates #4 and #6 are correctly decoded, theterminal device reports the HARQ-ACK indicating NACK and/or DTX in theHARQ-ACK reports #4 and #6.

The base station device notifies the terminal device of the informationfor releasing the scheduling of the SPDSCH through the PDCCH. Theterminal device stops monitoring of the set of set SPDSCH candidates.

By using the above method, the control information for scheduling theSPDSCH need not be notified individually, and thus the overhead for thecontrol information is reduced, and the latency is reduced. Further, theterminal device performs the HARQ-ACK for all the SPDSCH candidates, andthus even in a case in which the base station device does not transmitthe SPDSCH for that the terminal device, it is possible to recognizethat the terminal device is monitoring the SPDSCH candidates.

In the above-described method, in a case in which the same set of SPDSCHcandidates is set in a plurality of terminal devices, the resources forperforming the HARQ-ACK report are set differently between the terminaldevices. Accordingly, the transmission efficiency for the SPDSCH can beimproved, and the decrease in the transmission efficiency caused bycollision of the HARQ-ACK report can be reduced.

Other examples of the operation related to the HARQ-ACK report for theSPDSCH or the SPDSCH candidate in the terminal device are as follows.(1) In a case in which the terminal device can correctly receive(decode) the SPDSCH addressed to the terminal device, the terminaldevice reports ACK as the HARQ-ACK report for the SPDSCH throughpredetermined resources. Information indicating that it is a report ofthe terminal device may be explicitly or implicitly included in theHARQ-ACK report indicating ACK. (2) In a case in which the terminaldevice does not correctly receive (decode) the SPDSCH addressed to theterminal device, the terminal device does not perform the HARQ-ACKreport for the SPDSCH. In other words, the terminal device does nottransmit anything through predetermined resources used for the HARQ-ACKreport for the SPDSCH.

FIG. 10 is a diagram illustrating an example of SPDSCH transmission inthe base station device and the HARQ-ACK report in the terminal device.The base station device sets a set of SPDSCH candidates by performingthe STTI setting in the terminal device through the RRC signaling. Thebase station device notifies the terminal device of the information foractivating the scheduling of the SPDSCH through the PDCCH. The basestation device is likely to transmit the SPDSCH for the terminal deviceon the basis of the set of set SPDSCH candidates. On the other hand, theterminal device monitors the set of set SPDSCH candidates and detectsthe SPDSCH for the terminal device.

The base station device transmits the SPDSCH for the terminal device inSPDSCH candidates #1, #2, #3, and #5. Since the SPDSCHs in the SPDSCHcandidates #1, #2, and #5 are correctly decoded, the terminal devicereports the HARQ-ACK indicating ACK in the HARQ-ACK reports #1, #2, and#5. Since the SPDSCH in the SPDSCH candidate #3 is not correctlydecoded, the terminal device does not report the HARQ-ACK in theHARQ-ACK report #3, and transmits nothing.

The base station device transmits the SPDSCH for another the terminaldevice in SPDSCH candidates #4 and #6. Further, the base station devicemay not transmit anything in the SPDSCH candidates #4 and #6. Since theSPDSCHs in the SPDSCH candidates #4 and #6 are correctly decoded, theterminal device does not report the HARQ-ACK in the HARQ-ACK reports #4and #6, and transmits nothing.

The base station device notifies the terminal device of the informationfor releasing the scheduling of the SPDSCH through the PDCCH. Theterminal device stops monitoring of the set of set SPDSCH candidate.

FIG. 11 is a diagram illustrating a flowchart of the terminal device inwhich the STTI setting is set. The flowchart of FIG. 11 illustrates anoperation of the terminal device in a case in which the method describedin FIG. 10 is used. In step S1, the terminal device monitors the PDCCHincluding the information for activating the scheduling of the SPDSCH.In a case in which the PDCCH for the activation is detected, the processproceeds to step S2. In a case in which the PDCCH for the activation isnot detected, the process returns to step S1. In step S2, the terminaldevice monitors the PDCCH including the information for releasing thescheduling of the SPDSCH. In a case in which the PDCCH for the releaseis detected, the flow ends. In a case in which the PDCCH for the releaseis not detected, the process proceeds to step S3. In step S3, theterminal device monitors the SPDSCH candidate on the basis of the STTIsetting in the higher layer. In step S4, the terminal device detects theSPDSCH addressed to the terminal device from the SPDSCH candidate. In acase in which the SPDSCH addressed to the terminal device is correctlydecoded, the process proceeds to step S5. In a case in which the SPDSCHaddressed to that the terminal device is not decoded correctly, theprocess returns to step S2. In step S5, the terminal device reports theHARQ-ACK indicating ACK for the correctly decoded SPDSCH.

FIG. 12 is a diagram illustrating an example of operations of the basestation device and the terminal device in a case in which a settingrelated to the same SPDSCH is performed in a plurality of terminaldevices. In the example of FIG. 12, the base station device and theterminal device use the method described in FIG. 10. In other words, theterminal device performs the operation of the flowchart described inFIG. 11.

At a timing #1 of the SPDSCH candidate, the base station devicetransmits the SPDSCH addressed to a terminal device A. Since the SPDSCHaddressed to the terminal device A is correctly decoded, the terminaldevice A reports the HARQ-ACK indicating ACK for the SPDSCH. Since theterminal device B and the terminal device C do not decode the SPDSCHcandidate correctly, the terminal device B and the terminal device C donot report the HARQ-ACK for the SPDSCH candidate. The base stationdevice can recognize that the SPDSCH is correctly decoded on the basisof the HARQ-ACK report from the terminal device A.

At a timing #2 of the SPDSCH candidate, the base station devicetransmits the SPDSCH addressed to a terminal device C. Since the SPDSCHaddressed to the terminal device C is correctly decoded, the terminaldevice C reports the HARQ-ACK indicating ACK for the SPDSCH. Since theterminal device A and the terminal device B do not decode the SPDSCHcandidate correctly, the terminal device A and the terminal device B donot report the HARQ-ACK for the SPDSCH candidate. The base stationdevice can recognize that the SPDSCH is correctly decoded on the basisof the HARQ-ACK report from the terminal device C.

At a timing #3 of the SPDSCH candidate, the base station device does nottransmit anything. Since the terminal device A, the terminal device B,and the terminal device C do not decode the SPDSCH candidate correctly,the terminal device A, the terminal device B, and the terminal device Cdo not report the HARQ-ACK for the SPDSCH candidate.

At a timing #4 of the SPDSCH candidate, the base station devicetransmits the SPDSCH addressed to the terminal device B. Since theterminal device A, the terminal device B, and the terminal device C donot correctly decode the SPDSCH candidate, the terminal device A, theterminal device B, and the terminal device C do not report the HARQ-ACKfor the SPDSCH candidate. Since the HARQ-ACK for the SPDSCH candidate isnot reported, the base station device can recognize that the terminaldevice B does not correctly decode the SPDSCH.

By using the above method, the control information for scheduling theSPDSCH need not be notified individually, and thus the overhead for thecontrol information is reduced, and the latency is reduced. Further, theterminal device performs the HARQ-ACK only in a case in which the SPDSCHcandidate is correctly decoded, and thus a process and power consumptionof the terminal device can be reduced.

In the above-described method, in a case in which the same set of SPDSCHcandidates is set in a plurality of terminal devices, the resources forperforming the HARQ-ACK report are set commonly among the terminaldevices. Accordingly, the transmission efficiency for the SPDSCH can beimproved, the resources used for the HARQ-ACK report can be reduced, andthe uplink transmission efficiency can be improved.

Resource Element Mapping of SPDSCH in Present Embodiment

As described above, the channel in the STTI mode is mapped on the basisof the sub resource block. In other words, the SPDSCH is mapped on thebasis of the sub resource block. The resource element mapping of theSPDSCH described in the present embodiment is also applied to thecandidate of the SPDSCH to be monitored.

In the present embodiment, in a case in which a predetermined channel orsignal is not mapped to a predetermined resource element, apredetermined method can be used for the mapping. An example of thepredetermined method is rate matching. In the rate matching, apredetermined channel or signal is mapped while skipping a predeterminedresource element. It is necessary for the terminal device to recognizeor assume that the rate matching is used for mapping to a predeterminedresource element in reception (demodulation and decoding) of apredetermined channel or signal. Another example of the predeterminedmethod is puncturing. In the puncturing, a predetermined channel orsignal is assumed to be mapped without skipping a predetermined resourceelement, but another channel or signal is mapped to (overwritten in) thepredetermined resource element. It is preferable that the terminaldevice recognize or assume that the puncturing is used for the mappingto a predetermined resource element in the reception (demodulation,decoding) of a predetermined channel or signal, but the terminal devicemay not perform the recognizing or the assuming. In this case, thereception accuracy deteriorates, but the terminal device can perform thereception by adjusting the coding rate or the like. In the descriptionof the present embodiment, both the rate matching and the puncturing canbe applied as the resource element mapping.

The SPDSCH is mapped to the resource element on the basis of variousconditions, criteria, or scales. In other words, in each of the antennaports used for the transmission of the SPDSCH, a block of a complexvalue symbol is mapped to a resource element satisfying a predeterminedcondition, criterion, or scale in the (current) TTI serving as thetarget. The predetermined condition, criteria, or scale is at least partof the following conditions, criteria, or scales. The conditions,criteria, or scales used for mapping the SPDSCH (second PDSCH) to theresource element are also referred to as a second condition, a secondcriterion, or a second criterion, respectively. The conditions,criteria, or scales used for mapping the PDSCH (first PDSCH) to theresource element are also referred to as a first condition, a firstcriterion, or a first measure, respectively.

(1) The resource element to which the SPDSCH is mapped is within the subresource block allocated for transmission. Further, the resource elementto which the PDSCH is mapped is within the resource block allocated fortransmission.

(2) The resource element to which the SPDSCH is mapped is not used fortransmission of the PBCH and the synchronization signal. Further, theresource element to which the PDSCH is mapped is not used fortransmission of the PBCH and the synchronization signal.

(3) The resource element to which the SPDSCH is mapped is assumed not tobe used for the CRS by the terminal device. Further, the resourceelement to which the PDSCH is mapped is assumed not to be used for theCRS by the terminal device. The CRS assumed by the terminal device maybe different in the SPDSCH and the PDSCH. For example, the CRS assumedin the mapping of the SPDSCH is set independently of the CRS assumed inthe mapping of the SPDSCH.

(4) In the sub resource block in which the DMRS associated with theSPDSCH is not transmitted, the SPDSCH is transmitted through an antennaport through which the CRS is transmitted or an antenna port throughwhich the DMRS associated with the SPDSCH is transmitted. The DMRSassociated with the SPDSCH can be a DMRS mapped in the resource blockincluding the sub resource block to which the SPDSCH is mapped. Further,in the sub resource block in which the DMRS associated with the PDSCH isnot transmitted, the PDSCH is transmitted through the antenna port towhich the antenna port through which the CRS is transmitted istransmitted. The antenna port through which the SPDSCH is transmittedmay be identical to as or different from the antenna port through whichthe PDSCH is transmitted.

(5) In the sub resource block to which the DMRS associated with theSPDSCH is transmitted, the SPDSCH is transmitted through the antennaport through which the CRS is transmitted or the antenna port throughthe DMRS associated with the SPDSCH is transmitted. The DMRS associatedwith the SPDSCH can be a DMRS mapped in the resource block including thesub resource block to which the DMRS and/or the SPDSCH are mapped.Further, in the sub resource block through which the DMRS associatedwith the PDSCH is transmitted, the PDSCH is transmitted through theantenna port through which the DMRS associated with the PDSCH istransmitted. The antenna port through which the SPDSCH is transmittedmay be identical to or different from the antenna port through which thePDSCH is transmitted. In other words, the antenna port through which theDMRS associated with the SPDSCH is transmitted may be identical to ordifferent from the antenna port through which the DMRS associated withthe PDSCH is transmitted.

(6) In a case in which the SPDSCH is transmitted through an MBSFN subframe, the SPDSCH is transmitted through the antenna port through whichthe DMRS associated with the SPDSCH is transmitted. The DMRS associatedwith the SPDSCH can be a DMRS mapped in the resource block including thesub resource block to which the SPDSCH is mapped. The MBSFN sub frame isset in a cell-specific manner or a terminal device-specific mannerthrough the RRC signaling. Further, in a case in which the PDSCH istransmitted through the MBSFN sub frame, the PDSCH is transmittedthrough the antenna port through which the DMRS associated with thePDSCH is transmitted. The antenna port through which the SPDSCH istransmitted may be identical to or different from the antenna portthrough which the PDSCH is transmitted. In other words, the antenna portthrough which the DMRS associated with the SPDSCH is transmitted may beidentical to or different from the antenna port through which the DMRSassociated with the PDSCH is transmitted.

(7) The SPDSCH is not mapped to the resource elements used for the DMRSassociated with the SPDSCH. Further, the PDSCH is not mapped to theresource element used for the DMRS associated with the PDSCH. The DMRSassociated with the SPDSCH may be identical to or different from theDMRS associated with the PDSCH. Further, the SPDSCH may not be mapped tothe resource element used for the DMRS further associated with thePDSCH.

(8) The SPDSCH is not mapped to resource elements used for the ZP CSI-RSand/or the NZP CSI-RS set in a cell-specific manner or a terminaldevice-specific manner. Further, the PDSCH is not mapped to the resourceelements used for the ZP CSI-RS and/or the NZP CSI-RS set in acell-specific manner or a terminal device-specific manner. The ZP CSI-RSand/or the NZP CSI-RS in the mapping of the SPDSCH may have the samesetting as the ZP CSI-RS and/or the NZP CSI-RS in the mapping of thePDSCH.

(9) The SPDSCH is not mapped to the resource block pair, the subresource block, the enhanced resource element group, or the resourceelement for transmitting the EPDCCH associated with the SPDSCH. Forexample, the SPDSCH is not mapped to the sub resource block includingthe resource element to which the EPDCCH associated with the SPDSCH ismapped. Further, the PDSCH is not mapped to the resource block pair fortransmitting the EPDCCH associated with the PDSCH.

(10) The SPDSCH is mapped to a symbol after a symbol indicated by apredetermined index in a first slot in a certain sub frame in the subframe (the start symbol of the SPDSCH). In other words, in a case inwhich the sub resource block to which the SPDSCH is to be mappedincludes a symbol before the start symbol of the SPDSCH within a certainsub frame, the SPDSCH is not mapped to the symbol. The predeterminedindex indicating the start symbol of the SPDSCH is set in acell-specific manner or a terminal device-specific manner. For example,the predetermined index indicating the start symbol of the SPDSCH isincluded in the downlink STTI setting and set. A minimum value of thepredetermined index indicating the start symbol of the SPDSCH can be setto 0. Further, the start symbols of the SPDSCH may be specified inadvance without being set and can be set to, for example, 0. In otherwords, the SPDSCH can be mapped to all symbols in a certain sub frame.

Further, the PDSCH is mapped to a symbol after a symbol indicated by apredetermined index in a first slot in a certain sub frame in the subframe (the start symbol of the PDSCH). The predetermined indexindicating the start symbol of the SPDSCH may be identical to ordifferent from the predetermined index indicating the start symbol ofthe PDSCH. A minimum value of the predetermined index indicating thestart symbol of the PDSCH is 1.

(11) The SPDSCH is not mapped to the resource elements of the resourceelement group allocated to the PCFICH or the PHICH. Further, the PDSCHis not mapped to a symbol including the resource element group allocatedto the PCFICH or the PHICH (that is, a first symbol in a certain subframe). In other words, the SPDSCH can be mapped to resource elementsother than the resource element group in the symbol including theresource element group allocated to the PCFICH or the PHICH. For theresource element mapping of the SPDSCH, preferably, the rate matching isperformed in the resource element used for the transmission of thePCFICH or the PHICH.

(12) The SPDSCH is not mapped to the resource block pair, the subresource block, the symbol, the TTI, the resource element group, or theresource element for transmitting the PDCCH associated with the SPDSCH.In other words, the SPDSCH is not mapped to the resource block pairincluding the resource element or the resource element group, the subresource block, the symbol, the TTI, or the resource element group fortransmitting the PDCCH associated with the SPDSCH.

Further, the PDSCH is mapped regardless of the transmission of all thePDCCHs including the PDCCH associated with the PDSCH. For example, thePDCCH is transmitted through a symbol indicated by a CFI set or notifiedfrom the base station device, and the PDSCH is not mapped to the symbolused for transmitting the PDCCH. Therefore, in the mapping of the PDSCH,the terminal device may not necessarily recognize or assume the resourceelement used for transmitting the PDCCH.

On the other hand, in a case in which the SPDSCH is also mapped to thesymbol including the resource element used for transmitting the PDCCH,it is preferable that the terminal device recognize or assume theresource element used for transmitting the PDCCH in the mapping of thePDSCH. In the resource element mapping of the SPDSCH, preferably,puncturing is performed on the resource element used for transmittingthe PDCCH. Further, in the resource element mapping of the SPDSCH, thePDCCH includes not only the PDCCH associated with the SPDSCH but alsosome or all PDCCHs that the terminal device can recognize or receive.

(13-1) The SPDSCH is not mapped to the resource block, the resourceblock pair, or the resource block group used for the transmission of thePDSCH scheduled to (recognized or received by) the terminal device. Forexample, in a case in which a certain PDSCH is scheduled to a certainterminal device, the terminal device assumes that the SPDSCH is notmapped to the resource block used for transmission of the PDSCH or thesub resource block in the resource block group. Further, in this case,the SPDSCH may be mapped to the symbol (PDCCH region) before the startsymbol of the PDSCH in the resource block or the resource block group.

In a case in which the SPDSCH is not mapped to the resource block, theresource block pair, or the resource block group used for transmissionof the PDSCH scheduled to the terminal device, the PDSCH can be mappedregardless of the mapping of the SPDSCH. In other words, in a case inwhich the PDSCH is scheduled to resources including a certain resourceblock, the SPDSCH including the sub resource block in the resource blockis not mapped. In other words, the terminal device assumes that theSPDSCH using the sub resource block in the resource block used fortransmission of the PDSCH scheduled to the terminal device is not mapped(transmitted). The terminal device may not monitor the candidates of theSPDSCH.

In other words, in a case in which the candidate of the SPDSCH and thePDSCH to be scheduled collide in the same resource element, the resourceblock, or the sub resource block, the PDSCH is preferentially mapped,and the SPDSCH is not mapped.

(13-2) The SPDSCH is mapped regardless of transmission of the PDSCHscheduled to (recognized or received by) the terminal device. Forexample, even in a case in which a certain PDSCH is scheduled to acertain terminal device, the terminal device assumes that the SPDSCH canbe mapped to the resource block used for transmission of the PDSCH orthe sub resource block in the resource block group. In other words, theterminal device monitors the candidate of the SPDSCH to be setregardless of the scheduling of the PDSCH.

In a case in which the SPDSCH is mapped regardless of the transmissionof the PDSCH scheduled to the terminal device, the mapping of the PDSCHdepends on the SPDSCH. For example, the PDSCH is not mapped to theresource elements corresponding to the candidates of all the SPDSCHs.For example, the PDSCH is not mapped to the resource elementcorresponding to the SPDSCH which is detected among the candidates ofthe SPDSCH. In other words, the PDSCH is also mapped to the resourceelements corresponding to the SPDSCHs which is not detected among thecandidates of the SPDSCH.

Further, the PDSCH may not be scheduled in the resource blocks or thesub frames including the sub resource blocks used for transmission ofthe SPDSCH. For example, the terminal device assumes that the PDSCH isnot scheduled in the resource block or the sub frame including the subresource block corresponding to the candidate of the SPDSCH.

In other words, in a case in which the candidate of the SPDSCH and thePDSCH to be scheduled collide in the same resource element, the resourceblock, or the sub resource block, the SPDSCH is preferentially mapped,and the PDSCH is mapped to the resource element other than the resourceelement to which the SPDSCH is mapped.

(13-3) The resource element mappings described in (13-1) and (13-2) areswitched on the basis of a predetermined condition and used. Forexample, in a case in which the PDSCH is scheduled through the EPDCCH,the resource element mapping described in (13-1) is used, and in a casein which the PDSCH is scheduled through the PDCCH, the resource elementmapping described in (13-2) is used. For example, in a case in which thePDSCH is scheduled through the EPDCCH, the resource element mappingdescribed in (13-2) is used, and in a case in which the PDSCH isscheduled through the PDCCH, the resource element mapping described in(13-1) is used.

FIG. 13 is a diagram illustrating an example of the resource elementmapping of the SPDSCH. FIG. 13 illustrates resource elements of tworesource block pairs in the downlink. Resource elements R0 to R3 areresource elements to which the CRS is mapped respectively. Resourceelements C1 to C4 are resource elements to which the CSI-RS is mapped. Aresource element CFI is a resource element to which the PCFICH ismapped. A resource element HI is a resource element to which the PHICHis mapped.

In the example of FIG. 13, the TTI is a 1 symbol. In other words, onesub resource block is constituted by one symbol and 12 resource elementsindicated by 12 sub carriers. The terminal device receives or monitorsthe SPDSCH mapped to a set of sub resource blocks (resource blocks 0and 1) in a symbol 0 of a slot 0, a symbol 5 of the slot 0, and a symbol3 of a slot 1 on the basis of a predetermined setting. The SPDSCH in thesymbol 0 of the slot 0 is mapped to the resource elements other than theresource elements used for transmission of the CRS, the PCFICH, and thePHICH. The SPDSCH in the symbol 5 of the slot 0 is mapped to all theresource elements. The SPDSCH in the symbol 3 of the slot 1 is mapped toa resource element other than the resource element used for transmissionof the CSI-RS.

The SPDSCH may be further mapped after the start symbol of the SPDSCH ina certain sub frame. For example, in a case in which the start symbol ofthe SPDSCH is 3, the SPDSCH can be mapped from the symbol 3 of the slot0 to the symbol 6 of the slot 1. In the example of FIG. 13, the terminaldevice does not assume transmission or mapping of the SPDSCH in thesymbol 0 of the slot 0. Therefore, the terminal device may not receiveor monitor the SPDSCH in the symbol 0 of the slot 0.

Details of PDSCH and SPDSCH in Present Embodiment

For example, in a case in which the SPDSCH setting is performed in acertain serving cell, the terminal device performs a process for theSPDSCH in the serving cell. Further, in a case in which the SPDSCHsetting is not performed in a certain serving cell, the terminal deviceperforms a process for the PDSCH in the serving cell. Hereinafter, anexample of a difference between the PDSCH and the SPDSCH will bedescribed.

An example of the difference between the PDSCH and the SPDSCH is the TTIsize.

The PDSCH is the downlink shared channel in the first TTI mode andtransmitted on the basis of the TTI specified by one sub frame used inthe system of the related art.

The SPDSCH is the downlink shared channel in the second TTI mode (STTImode) and transmitted on the basis of a TTI specified or set by aninteger multiple of the symbol length which is not used in the system ofthe related art.

An example of the difference between PDSCH and SPDSCH is the schedulingmethod.

The PDSCH can be scheduled through the DCI notified through the PDCCHdetected in the same TTI. Specifically, the TTI to which the PDSCH ismapped is a TTI in which the corresponding PDCCH is detected. Theresource block in the frequency domain to which the PDSCH is mapped isscheduled through the DCI. In other words, the PDCCH for scheduling acertain PDSCH schedules only the PDSCH.

The SPDSCH may not be scheduled through the DCI notified through thecontrol channel or the PDCCH detected in the same TTI. The TTI to whichthe SPDSCH can be mapped is a predetermined TTI set through the RRCsignaling. The sub resource block in the frequency domain to which theSPDSCH can be mapped may be set and/or notified through the DCI foractivating the scheduling of the RRC signaling and/or the SPDSCH. Inother words, the SPDSCH is scheduled using one or more SPDSCH candidatesset through the DCI for activating the RRC signaling and the schedulingof the SPDSCH.

An example of the difference between PDSCH and SPDSCH is the receptionprocess of the terminal device.

In the first TTI mode, the PDSCH received by a certain terminal deviceis the PDSCH for the terminal device. Therefore, the terminal deviceperforms the HARQ-ACK report for the PDSCH scheduled for the terminaldevice regardless of a result of decoding the PDSCH.

In the second TTI mode, the SPDSCH (SPDSCH candidate) received by acertain terminal device is unlikely to be the PDSCH for the terminaldevice. Therefore, the terminal device performs the HARQ-ACK report forthe PDSCH scheduled for the terminal device on the basis of a result ofdecoding the PDSCH. For example, in a case in which the result ofdecoding the PDSCH is ACK, the terminal device reports the HARQ-ACKreport for the PDSCH scheduled for the terminal device. In a case inwhich the result of decoding the PDSCH is NACK, the terminal device doesnot report the HARQ-ACK report for the PDSCH scheduled for the terminaldevice.

Details of Reference Signal Used for Demodulating SPDSCH in PresentEmbodiment

In the present embodiment, the SPDSCH can be demodulated (received)using various reference signals. In other words, the SPDSCH can betransmitted from various antenna ports.

An example of the reference signal used for demodulating the SPDSCH is areference signal mapped in a predetermined region decided on the basisof resources (symbols or sub resource blocks) to which the SPDSCH ismapped. For example, the reference signal is a CRS, and the SPDSCH istransmitted through an antenna port from which the CRS is transmitted.The terminal device demodulates the SPDSCH using the CRS. Further, forexample, the reference signal is a DM-RS mapped to a predeterminedresource element, and the SPDSCH is transmitted through an antenna portfrom which the DM-RS is transmitted. The terminal device demodulates theSPDSCH using the DM-RS. The DM-RS can have a configuration (signal)similar to the DM-RS associated with the PDSCH.

FIG. 14 is a diagram illustrating an example of the reference signalused for demodulating the SPDSCH in the present embodiment. Asillustrated in FIG. 14, in a case in which the SPDSCH is transmittedthrough a symbol 2 of a slot 0 of a sub frame 1, the SPDSCH isdemodulated using the reference signal mapped in a predetermined regiondecided on the basis of the symbol 2 of the slot 0 of the sub frame 1.

An example of a predetermined region to which the reference signal usedfor demodulating the SPDSCH is mapped is a symbol to which the SPDSCH ismapped and/or a symbol before the symbol to which the SPDSCH is mapped.In other words, the reference signal used for demodulating the SPDSCH isa reference signal mapped to the symbol to which the SPDSCH is mappedand/or the symbol before the symbol to which the SPDSCH is mapped. Inthe example of FIG. 14, the SPDSCH is demodulated using the referencesignal mapped to the symbol before the symbol 2 of the slot 0 of the subframe 1. Therefore, the SPDSCH can be demodulated even when a symbolafter the symbol to which the SPDSCH is mapped is not received, and thusthe latency is reduced. Further, since the SPDSCH is demodulated usingthe most recent reference signal, influence on a time variation in thepropagation path can be reduced.

Another example of the predetermined region to which the referencesignal used for the demodulation of the SPDSCH is mapped is symbols froma symbol which is a predetermined number of symbols earlier than thesymbol to which the SPDSCH is mapped to the symbol to which the SPDSCHis mapped. For example, the predetermined number of symbols may bespecified in advance or may be set through RRC signaling. For example,the predetermined number of symbols is the number of symbolsconstituting one sub frame. For example, the predetermined number ofsymbols is 14. In other words, the SPDSCH is demodulated using thereference signal mapped to the 14 symbols before the symbol to which theSPDSCH is mapped. In the example of FIG. 14, the SPDSCH is demodulatedusing the reference signal mapped to the symbols from the symbol 3 ofthe slot 0 of the sub frame 0 to the symbol 2 of the slot 0 of the subframe 1. Therefore, the SPDSCH can be demodulated even when the symbolafter the symbol to which the SPDSCH is mapped is not received, and thusthe latency is reduced. Further, since the SPDSCH is demodulated usingthe most recent reference signal, the influence on the time variation inthe propagation path can be reduced. Further, since the SPDSCH isdemodulated using the reference signal mapped to a predetermined numberof symbols, the variation in the accuracy of demodulation is reduced.

Another example of the predetermined region to which the referencesignal used for demodulating the SPDSCH is mapped is a sub frame whichis a predetermined number of sub frames before the sub frame includingthe symbol to which the SPDSCH is mapped. For example, the predeterminednumber is 1, and the predetermined region is a sub frame immediatelybefore the sub frame including the symbol to which the SPDSCH is mapped.In the example of FIG. 14, the SPDSCH is demodulated using the referencesignal mapped to the sub frame 1. Therefore, the SPDSCH can bedemodulated even when the symbol after the symbol to which the SPDSCH ismapped is not received, and thus the latency is reduced. Further, sincethe SPDSCH is demodulated using the reference signal mapped to a 1 subframe, similarly to the PDSCH of the related art, the variation in theaccuracy of demodulation is reduced.

Another example of the reference signal used for demodulating the SPDSCHis a reference signal mapped within a sub resource block to which theSPDSCH is mapped. The reference signal is a demodulation referencesignal (a DM-RS, a URS, or an SPDSCH-DMRS) associated with the SPDSCH.The SPDSCH is transmitted through an antenna port from which thedemodulation reference signal associated with the SPDSCH is transmitted(mapped). The terminal device demodulates the SPDSCH using theSPDSCH-DMRS. The SPDSCH-DMRS is generated (mapped) on the basis ofvarious methods or rules.

In one example of the SPDSCH-DMRS mapping method, the SPDSCH-DMRS ismapped to a predetermined resource element in the sub resource block towhich the SPDSCH is mapped. The predetermined resource element may bespecified in advance or may be set through RRC signaling. Further, thepredetermined resource element may be specified or set in accordancewith the symbol to be mapped. Further, the predetermined resourceelement may be decided in accordance with the resource element to whichanother channel or signal including the CRS, the PHICH, the PCFICH, thePBCH, the PSS, or the SSS is mapped. For example, the predeterminedresource element is mapped to be a resource element other than theresource element to which another channel or signal is mapped. Further,in a case in which the resource element to which the SPDSCH-DMRS ismapped is the resource element to which another channel or signal ismapped, any one of the SPDSCH-DMRS or another channel or signal ismapped to the resource element on the basis of predetermined criteria.

In another example of the SPDSCH-DMRS mapping method, the SPDSCH-DMRS ismultiplexed into the SPDSCH mapped to the resource element. For example,the SPDSCH-DMRS is multiplexed into the SPDSCH through a predeterminedmethod before being mapped to the resource element. As a method ofmultiplexing the SPDSCH-DMRS into the SPDSCH, various methods can beused. The SPDSCH into which the SPDSCH-DMRS is multiplexed is mapped tothe resource element. The SPDSCH can be mapped while avoiding theresource element to which a predetermined channel or signal is mappedusing various methods already described above, and thus the SPDSCH-DMRSis mapped with a predetermined density.

FIG. 15 is a diagram illustrating an example of the reference signalused for demodulating the SPDSCH in the present embodiment. In theexample of FIG. 15, the TTI size is 1 sub frame, and three SPDSCHs(including SPDSCH candidates) are mapped to a symbol 0 of a slot 0, asymbol 5 of a slot 0, and a symbol 3 of a slot 1. The SPDSCH-DMRS ismultiplexed into each of the SPDSCHs before being mapped to the resourceelement.

In the method of multiplexing the SPDSCH-DMRS into the SPDSCH, theSPDSCH-DMRS is periodically multiplexed into the SPDSCH on the basis ofa predetermined period and a predetermined offset. The predeterminedperiod and the predetermined offset may be specified in advance ordecided through RRC signaling. Further, the predetermined period and thepredetermined offset may be specified or set depending on the symbol. Inthe example of FIG. 15, the SPDSCH-DMRS is multiplexed into the SPDSCHwith a period of 3 and an offset of 0.

According to the details of the above embodiment, it is possible toimprove the transmission efficiency in the wireless communication systemin which the base station device 1 and the terminal device 2 communicatewith each other.

APPLICATION EXAMPLES Application Examples for Base Station FirstApplication Example

FIG. 16 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 and the base stationapparatus 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or a plurality of antennaelements (e.g., a plurality of antenna elements constituting a MIMOantenna) and is used for the base station apparatus 820 to transmit andreceive a wireless signal. The eNB 800 may include the plurality of theantennas 810 as illustrated in FIG. 16, and the plurality of antennas810 may, for example, correspond to a plurality of frequency bands usedby the eNB 800. It should be noted that while FIG. 16 illustrates anexample in which the eNB 800 includes the plurality of antennas 810, theeNB 800 may include the single antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of an upper layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data in asignal processed by the wireless communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may generate a bundled packet by bundling data from aplurality of base band processors to transfer the generated bundledpacket. Further, the controller 821 may also have a logical function ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, and scheduling. Further, thecontrol may be performed in cooperation with a surrounding eNB or a corenetwork node. The memory 822 includes a RAM and a ROM, and stores aprogram executed by the controller 821 and a variety of control data(such as, for example, terminal list, transmission power data, andscheduling data).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to the core network 824. The controller821 may communicate with a core network node or another eNB via thenetwork interface 823. In this case, the eNB 800 may be connected to acore network node or another eNB through a logical interface (e.g., S1interface or X2 interface). The network interface 823 may be a wiredcommunication interface or a wireless communication interface forwireless backhaul. In the case where the network interface 823 is awireless communication interface, the network interface 823 may use ahigher frequency band for wireless communication than a frequency bandused by the wireless communication interface 825.

The wireless communication interface 825 supports a cellularcommunication system such as long term evolution (LTE) or LTE-Advanced,and provides wireless connection to a terminal located within the cellof the eNB 800 via the antenna 810. The wireless communication interface825 may typically include a base band (BB) processor 826, an RF circuit827, and the like. The BB processor 826 may, for example, performencoding/decoding, modulation/demodulation, multiplexing/demultiplexing,and the like, and performs a variety of signal processing on each layer(e.g., L1, medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP)). The BB processor 826 may havepart or all of the logical functions as described above instead of thecontroller 821. The BB processor 826 may be a module including a memoryhaving a communication control program stored therein, a processor toexecute the program, and a related circuit, and the function of the BBprocessor 826 may be changeable by updating the program. Further, themodule may be a card or blade to be inserted into a slot of the basestation apparatus 820, or a chip mounted on the card or the blade.Meanwhile, the RF circuit 827 may include a mixer, a filter, anamplifier, and the like, and transmits and receives a wireless signalvia the antenna 810.

The wireless communication interface 825 may include a plurality of theBB processors 826 as illustrated in FIG. 16, and the plurality of BBprocessors 826 may, for example, correspond to a plurality of frequencybands used by the eNB 800. Further, the wireless communication interface825 may also include a plurality of the RF circuits 827, as illustratedin FIG. 16, and the plurality of RF circuits 827 may, for example,correspond to a plurality of antenna elements. Note that FIG. 16illustrates an example in which the wireless communication interface 825includes the plurality of BB processors 826 and the plurality of RFcircuits 827, but the wireless communication interface 825 may includethe single BB processor 826 or the single RF circuit 827.

Second Application Example

FIG. 17 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station apparatus 850, and an RRH 860. Each of the antennas 840and the RRH 860 may be connected to each other via an RF cable. Further,the base station apparatus 850 and the RRH 860 may be connected to eachother by a high speed line such as optical fiber cables.

Each of the antennas 840 includes a single or a plurality of antennaelements (e.g., antenna elements constituting a MIMO antenna), and isused for the RRH 860 to transmit and receive a wireless signal. The eNB830 may include a plurality of the antennas 840 as illustrated in FIG.17, and the plurality of antennas 840 may, for example, correspond to aplurality of frequency bands used by the eNB 830. Note that FIG. 17illustrates an example in which the eNB 830 includes the plurality ofantennas 840, but the eNB 830 may include the single antenna 840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are similar to the controller 821, the memory 822,and the network interface 823 described with reference to FIG. 16.

The wireless communication interface 855 supports a cellularcommunication system such as LTE and LTE-Advanced, and provides wirelessconnection to a terminal located in a sector corresponding to the RRH860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include a BB processor 856 or the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 16 except that the BB processor 856 is connected to anRF circuit 864 of the RRH 860 via the connection interface 857. Thewireless communication interface 855 may include a plurality of the BBprocessors 856, as illustrated in FIG. 17, and the plurality of BBprocessors 856 may, for example, correspond to a plurality of frequencybands used by the eNB 830. Note that FIG. 17 illustrates an example inwhich the wireless communication interface 855 includes the plurality ofBB processors 856, but the wireless communication interface 855 mayinclude the single BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may be a communication module forcommunication on the high speed line which connects the base stationapparatus 850 (wireless communication interface 855) to the RRH 860.

Further, the RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station apparatus850. The connection interface 861 may be a communication module forcommunication on the high speed line.

The wireless communication interface 863 transmits and receives awireless signal via the antenna 840. The wireless communicationinterface 863 may typically include the RF circuit 864 or the like. TheRF circuit 864 may include a mixer, a filter, an amplifier and the like,and transmits and receives a wireless signal via the antenna 840. Thewireless communication interface 863 may include a plurality of the RFcircuits 864 as illustrated in FIG. 17, and the plurality of RF circuits864 may, for example, correspond to a plurality of antenna elements.Note that FIG. 17 illustrates an example in which the wirelesscommunication interface 863 includes the plurality of RF circuits 864,but the wireless communication interface 863 may include the single RFcircuit 864.

The eNB 800, the eNB 830, the base station device 820, or the basestation device 850 illustrated in FIGS. 16 and 17 may correspond to thebase station device 1 described above with reference to FIG. 3 and thelike.

Application Examples for Terminal Apparatus First Application Example

FIG. 18 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 as the terminal apparatus 2 to whichthe technology according to the present disclosure may be applied. Thesmartphone 900 includes a processor 901, a memory 902, a storage 903, anexternal connection interface 904, a camera 906, a sensor 907, amicrophone 908, an input device 909, a display device 910, a speaker911, a wireless communication interface 912, one or more antennaswitches 915, one or more antennas 916, a bus 917, a battery 918, and anauxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on chip (SoC),and controls the functions of an application layer and other layers ofthe smartphone 900. The memory 902 includes a RAM and a ROM, and storesa program executed by the processor 901 and data. The storage 903 mayinclude a storage medium such as semiconductor memories and hard disks.The external connection interface 904 is an interface for connecting thesmartphone 900 to an externally attached device such as memory cards anduniversal serial bus (USB) devices.

The camera 906 includes, for example, an image sensor such as chargecoupled devices (CCDs) and complementary metal oxide semiconductor(CMOS), and generates a captured image. The sensor 907 may include asensor group including, for example, a positioning sensor, a gyrosensor, a geomagnetic sensor, an acceleration sensor and the like. Themicrophone 908 converts a sound that is input into the smartphone 900 toan audio signal. The input device 909 includes, for example, a touchsensor which detects that a screen of the display device 910 is touched,a key pad, a keyboard, a button, a switch or the like, and accepts anoperation or an information input from a user. The display device 910includes a screen such as liquid crystal displays (LCDs) and organiclight emitting diode (OLED) displays, and displays an output image ofthe smartphone 900. The speaker 911 converts the audio signal that isoutput from the smartphone 900 to a sound.

The wireless communication interface 912 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude the BB processor 913, the RF circuit 914, and the like. The BBprocessor 913 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 914 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 916. The wireless communicationinterface 912 may be a one-chip module in which the BB processor 913 andthe RF circuit 914 are integrated. The wireless communication interface912 may include a plurality of BB processors 913 and a plurality of RFcircuits 914 as illustrated in FIG. 18. Note that FIG. 18 illustrates anexample in which the wireless communication interface 912 includes aplurality of BB processors 913 and a plurality of RF circuits 914, butthe wireless communication interface 912 may include a single BBprocessor 913 or a single RF circuit 914.

Further, the wireless communication interface 912 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelesslocal area network (LAN) system in addition to the cellularcommunication system, and in this case, the wireless communicationinterface 912 may include the BB processor 913 and the RF circuit 914for each wireless communication system.

Each antenna switch 915 switches a connection destination of the antenna916 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 912.

Each of the antennas 916 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 912. The smartphone 900 may include aplurality of antennas 916 as illustrated in FIG. 18. Note that FIG. 18illustrates an example in which the smartphone 900 includes a pluralityof antennas 916, but the smartphone 900 may include a single antenna916.

Further, the smartphone 900 may include the antenna 916 for eachwireless communication system. In this case, the antenna switch 915 maybe omitted from a configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies electric power toeach block of the smartphone 900 illustrated in FIG. 18 via a feederline that is partially illustrated in the figure as a dashed line. Theauxiliary controller 919, for example, operates a minimally necessaryfunction of the smartphone 900 in a sleep mode.

Second Application Example

FIG. 19 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied. The car navigationapparatus 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a wireless communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC, and controls thenavigation function and the other functions of the car navigationapparatus 920. The memory 922 includes a RAM and a ROM, and stores aprogram executed by the processor 921 and data.

The GPS module 924 uses a GPS signal received from a GPS satellite tomeasure the position (e.g., latitude, longitude, and altitude) of thecar navigation apparatus 920. The sensor 925 may include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, abarometric sensor and the like. The data interface 926 is, for example,connected to an in-vehicle network 941 via a terminal that is notillustrated, and acquires data such as vehicle speed data generated onthe vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g., CD or DVD) inserted into the storage medium interface 928. Theinput device 929 includes, for example, a touch sensor which detectsthat a screen of the display device 930 is touched, a button, a switchor the like, and accepts operation or information input from a user. Thedisplay device 930 includes a screen such as LCDs and OLED displays, anddisplays an image of the navigation function or the reproduced content.The speaker 931 outputs a sound of the navigation function or thereproduced content.

The wireless communication interface 933 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude the BB processor 934, the RF circuit 935, and the like. The BBprocessor 934 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 935 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 937. The wireless communicationinterface 933 may be a one-chip module in which the BB processor 934 andthe RF circuit 935 are integrated. The wireless communication interface933 may include a plurality of BB processors 934 and a plurality of RFcircuits 935 as illustrated in FIG. 19. Note that FIG. 19 illustrates anexample in which the wireless communication interface 933 includes aplurality of BB processors 934 and a plurality of RF circuits 935, butthe wireless communication interface 933 may include a single BBprocessor 934 or a single RF circuit 935.

Further, the wireless communication interface 933 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelessLAN system in addition to the cellular communication system, and in thiscase, the wireless communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each wireless communicationsystem.

Each antenna switch 936 switches a connection destination of the antenna937 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 933.

Each of the antennas 937 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 933. The car navigation apparatus 920may include a plurality of antennas 937 as illustrated in FIG. 19. Notethat FIG. 19 illustrates an example in which the car navigationapparatus 920 includes a plurality of antennas 937, but the carnavigation apparatus 920 may include a single antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each wireless communication system. In this case, the antenna switch936 may be omitted from a configuration of the car navigation apparatus920.

The battery 938 supplies electric power to each block of the carnavigation apparatus 920 illustrated in FIG. 19 via a feeder line thatis partially illustrated in the figure as a dashed line. Further, thebattery 938 accumulates the electric power supplied from the vehicle.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation apparatus 920, the in-vehicle network 941, and a vehiclemodule 942. The vehicle module 942 generates vehicle data such asvehicle speed, engine speed, and trouble information, and outputs thegenerated data to the in-vehicle network 941.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A terminal device that communicates with a base station device,including:

a higher layer processing unit configured to set an STTI channel settingthrough signaling of a higher layer from the base station device; and

a receiving unit configured to receive a first PDSCH in a case in whichthe STTI channel setting is not set and receive a second PDSCH in a casein which the STTI channel setting is set,

in which the first PDCCH is mapped to one or more resource blocks,

the second PDCCH is mapped to one or more sub resource blocks, and

the second PDSCH is demodulated using a reference signal mapped to asymbol including the sub resource block or a resource element before thesymbol.

(2)

The terminal device according to (1), in which the reference signal is acell-specific reference signal.

(3)

The terminal device according to (1), in which the reference signal is ademodulation reference signal associated with the second PDSCH.

(4)

The terminal device according to (3), in which the demodulationreference signal is mapped to a predetermined resource element includedin the sub resource block.

(5)

The terminal device according to (3), in which the demodulationreference signal is multiplexed into the second PDSCH on a basis of apredetermined period and a predetermined offset.

(6)

The terminal device according to any one of (1) to (5), in which anumber of symbols of the sub resource block is smaller than a number ofsymbols corresponding to the resource block.

(7) The terminal device according to (1), in which the second PDSCH ismapped to any one of one or more second PDSCH candidates set on a basisof the STTI channel setting.

(8)

The terminal device according to (7), in which the receiving unitperforms a reception process on all the second PDSCH candidates.

(9)

A base station device that communicates with a terminal device,including:

a higher layer processing unit configured to set an STTI channel settingin the terminal device through signaling of a higher layer; and

a transmitting unit configured to transmit a first PDSCH in a case inwhich the STTI channel setting is not set and transmit a second PDSCH ina case in which the STTI channel setting is set,

in which the first PDCCH is mapped to one or more resource blocks,

the second PDCCH is mapped to one or more sub resource blocks, and

the second PDSCH is demodulated using a reference signal mapped to asymbol including the sub resource block or a resource element before thesymbol.

(10)

A communication method used in a terminal device that communicates witha base station device, including:

a step of setting an STTI channel setting through signaling of a higherlayer from the base station device; and

a step of receiving a first PDSCH in a case in which the STTI channelsetting is not set and receiving a second PDSCH in a case in which theSTTI channel setting is set,

in which the first PDCCH is mapped to one or more resource blocks,

the second PDCCH is mapped to one or more sub resource blocks, and

the second PDSCH is demodulated using a reference signal mapped to asymbol including the sub resource block or a resource element before thesymbol.

(11)

A communication method used in a base station device that communicateswith a terminal device, including:

a step of setting an STTI channel setting in the terminal device throughsignaling of a higher layer; and

a step of transmitting a first PDSCH in a case in which the STTI channelsetting is not set and transmitting a second PDSCH in a case in whichthe STTI channel setting is set,

in which the first PDCCH is mapped to one or more resource blocks,

the second PDCCH is mapped to one or more sub resource blocks, and

the second PDSCH is demodulated using a reference signal mapped to asymbol including the sub resource block or a resource element before thesymbol.

REFERENCE SIGNS LIST

-   1 base station device-   2 terminal device-   101, 201 higher layer processing unit-   103, 203 control unit-   105, 205 receiving unit-   107, 207 transmitting unit-   109, 209 transceiving antenna-   1051, 2051 decoding unit-   1053, 2053 demodulating unit-   1055, 2055 demultiplexing unit-   1057, 2057 wireless receiving unit-   1059, 2059 channel measuring unit-   1071, 2071 encoding unit-   1073, 2073 modulating unit-   1075, 2075 multiplexing unit-   1077, 2077 wireless transmitting unit-   1079 downlink reference signal generating unit-   2079 uplink reference signal generating unit

The invention claimed is:
 1. A terminal device that communicates with abase station device, the terminal device comprising: circuitryconfigured to: set an STTI channel setting through signaling of a higherlayer from the base station device; receive a first PDSCH in a case inwhich the STTI channel setting is not set; and receive a second PDSCH ina case in which the STTI channel setting is set, wherein the first PDSCHis transmitted by using a first TTI based on one subframe, wherein thesecond PDSCH is transmitted by using a second TTI composed of apredetermined number of symbols shorter than the subframe, the secondTTI being set in accordance with a use of data, wherein a referencesignal for the second PDSCH is mapped to a predetermined resourceelement in the second TTI, or to a predetermined resource element inother second TTI which is prior to the second TTI, wherein thepredetermined resource element is determined by the resource element ofa cell-specific reference signal to be mapped by shifting in frequencydirection based on a predetermined value, wherein the second PDSCH ismapped to any one of one or more second PDSCH candidates set on a basisof the STTI channel setting, wherein the one or more second PDSCHcandidates are monitored at the terminal device, and an acknowledgementis reported to the base station only in a case in which at least one ofthe monitored second PDSCH candidates is decoded, the acknowledgmentbeing reported by using a resource shared with another terminal device,when same set of the one or more second PDSCH candidates is set amongthe terminal device and the other terminal device.
 2. The terminaldevice according to claim 1, wherein the predetermined resource elementis a resource element other than the resource element of thecell-specific reference signal.
 3. The terminal device according toclaim 1, wherein the second TTI is defined in each of two slots thatconstitute the subframe.
 4. The terminal device according to claim 1,wherein the reference signal is mapped to the predetermined resourceelement included in the subframe.
 5. The terminal device according toclaim 1, wherein the reference signal is multiplexed into the secondPDSCH on a basis of a predetermined period and a predetermined offset.6. The terminal device according to claim 1, wherein a number of symbolsof the predetermined resource element is smaller than a number ofsymbols corresponding to the subframe.
 7. The terminal device accordingto claim 1, wherein the circuitry performs a reception process on allthe second PDSCH candidates.
 8. A base station device that communicateswith a terminal device, the base station comprising: circuitryconfigured to: set an STTI channel setting in the terminal devicethrough signaling of a higher layer; transmit a first PDSCH in a case inwhich the STTI channel setting is not set; and transmit a second PDSCHin a case in which the STTI channel setting is set, wherein the firstPDSCH is transmitted by using a first TTI based on one subframe, whereinthe second PDSCH is transmitted by using a second TTI composed of apredetermined number of symbols shorter than the subframe, the secondTTI being set in accordance with a use of data, wherein a referencesignal for the second PDSCH is mapped to a predetermined resourceelement in the second TTI, or to a predetermined resource element inother second TTI which is prior to the second TTI, wherein thepredetermined resource element is determined by the resource element ofa cell-specific reference signal to be mapped by shifting in frequencydirection based on a predetermined value, wherein the second PDSCH ismapped to any one of one or more second PDSCH candidates set on a basisof the STTI channel setting, wherein the one or more second PDSCHcandidates are monitored at the terminal device, and an acknowledgementis reported from the terminal device only in a case in which at leastone of the monitored second PDSCH candidates is decoded, theacknowledgment being reported by using a resource shared with anotherterminal device, when same set of the one or more second PDSCHcandidates is set among the terminal device and the other terminaldevice.
 9. A communication method used in a terminal device thatcommunicates with a base station device, the communication methodcomprising: setting an STTI channel setting through signaling of ahigher layer from the base station device; receiving a first PDSCH in acase in which the STTI channel setting is not set; and receiving asecond PDSCH in a case in which the STTI channel setting is set, whereinthe first PDSCH is transmitted by using a first TTI based on onesubframe, wherein the second PDSCH is transmitted by using a second TTIcomposed of a predetermined number of symbols shorter than the subframe,the second TTI being set in accordance with a use of data, wherein areference signal for the second PDSCH is mapped to a predeterminedresource element in the second TTI, or to a predetermined resourceelement in other second TTI which is prior to the second TTI, whereinthe predetermined resource element is determined by the resource elementof a cell-specific reference signal to be mapped by shifting infrequency direction based on a predetermined value, wherein the secondPDSCH is mapped to any one of one or more second PDSCH candidates set ona basis of the STTI channel setting, wherein the one or more secondPDSCH candidates are monitored at the terminal device, and anacknowledgement is reported to the base station only in a case in whichat least one of the monitored second PDSCH candidates is decoded, theacknowledgment being reported by using a resource shared with anotherterminal device, when same set of the one or more second PDSCHcandidates is set among the terminal device and the other terminaldevice.
 10. A communication method used in a base station device thatcommunicates with a terminal device, the communication methodcomprising: setting an STTI channel setting in the terminal devicethrough signaling of a higher layer; transmitting a first PDSCH in acase in which the STTI channel setting is not set; and transmitting asecond PDSCH in a case in which the STTI channel setting is set, whereinthe first PDSCH is transmitted by using a first TTI based on onesubframe, wherein the second PDSCH is transmitted by using a second TTIcomposed of a predetermined number of symbols shorter than the subframe,the second TTI being set in accordance with a use of data, wherein areference signal for the second PDSCH is mapped to a predeterminedresource element in the second TTI, or to a predetermined resourceelement in other second TTI which is prior to the second TTI, whereinthe predetermined resource element is determined by the resource elementof a cell-specific reference signal to be mapped by shifting infrequency direction based on a predetermined value, wherein the secondPDSCH is mapped to any one of one or more second PDSCH candidates set ona basis of the STTI channel setting, wherein the one or more secondPDSCH candidates are monitored at the terminal device, and anacknowledgement is reported from the terminal device only in a case inwhich at least one of the monitored second PDSCH candidates is decoded,the resource for the acknowledgment being reported by using a resourceshared with another terminal device, when same set of the one or moresecond PDSCH candidates is set among the terminal device and the otherterminal device.